Automatic Shelf Registration Statement (Form S-3ASR)

As filed with the Securities and Exchange Commission on October 10, 2025

Registration No. 333-

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM S-3
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

NioCorp Developments Ltd.

(Exact name of registrant as specified in its charter)

British Columbia, Canada (State or other jurisdiction of incorporation or organization)			98-1262185 (I.R.S. Employer Identification Number)
7000 South Yosemite Street, Suite 115 Centennial, Colorado 80112 Tel: (720) 334-7066 (Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)
CT Corporation System 28 Liberty Street Floor 42 New York, New York 10005 Tel: (212) 894-8940 (Name, address, including zip code, and telephone number, including area code, of agent for service)
Copies of all communications, including communications sent to agent for service, should be sent to:
Christopher M. Kelly Andrew C. Thomas Andrew D. Iammarino Jones Day North Point 901 Lakeside Avenue Cleveland, Ohio 44114 (216) 586-3939		Bob Wooder Kyle Misewich Blake, Cassels & Graydon LLP 1133 Melville Street Suite 3500 Vancouver, British Columbia V6E 4E5

Approximate date of commencement of proposed sale to the public: From time to time after the effectiveness of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box: ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box: ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ☒

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large Accelerated Filer ☐	Accelerated filer ☐
Non-Accelerated Filer ☒	Smaller Reporting Company ☒
	Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

PROSPECTUS

NioCorp Developments Ltd.

Common Shares
Common Share Purchase Warrants
Debt Securities
Units

We may offer and sell, from time to time, common shares, without par value ("Common Shares"), Common Share purchase warrants ("Warrants"), or debt securities, as well as units that include any of these securities, or any combination thereof. We may sell any combination of these securities in one or more offerings in amounts, at prices and on terms that we determine at the time of the offering.

This prospectus describes the general manner in which the securities listed above may be offered and sold. The specific manner in which such securities may be offered and sold will be described in one or more prospectus supplements. You should carefully read this prospectus and any accompanying prospectus supplement, together with the documents we incorporate by reference, before you invest in our securities.

We may sell securities directly or to or through underwriters or dealers, and also to other purchasers or through agents. The names of any underwriters or agents that are included in a sale of such securities to you, and any applicable commissions or discounts, will be stated in an accompanying prospectus supplement.

Our Common Shares trade on The Nasdaq Global Market under the symbol "NB." On October 9, 2025, the last reported sale price of our Common Shares on The Nasdaq Global Market was $9.84 per Common Share.

Investing in our securities involves a high degree of risk. See "Risk Factors" beginning on page 2 of this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is October 10, 2025.

TABLE OF CONTENTS

Page

About This Prospectus	ii
Where You Can Find More Information	iii
Information Incorporated by Reference	iv
Summary	1
Risk Factors	2
Cautionary Note Regarding Forward-Looking Statements	3
Use of Proceeds	5
Description of Capital Stock	6
Description of Warrants	11
Description of Debt Securities	13
Description of Units	21
Plan of Distribution	22
Legal Matters	23
Experts	24

About This Prospectus

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission (the "SEC") using a "shelf" registration process. The Company may offer and sell from time to time any combination of the securities described in this prospectus in one or more offerings in amounts, at prices and on terms that we determine at the time of the offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the type or series of securities offered and the terms of that offering.

This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

You should rely only on the information provided in this prospectus, as well as the information incorporated by reference into this prospectus and any applicable prospectus supplement. We have not authorized anyone to provide you with different information. We have not authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus or any applicable prospectus supplement or any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We do not take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. You should not assume that the information in this prospectus or any applicable prospectus supplement is accurate as of any date other than the date of the applicable document. Since the date of this prospectus and the documents incorporated by reference into this prospectus, our business, financial condition, results of operations and prospects may have changed. We will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted.

We may also provide a prospectus supplement or post-effective amendment to the registration statement of which this prospectus is a part to add information to, or update or change information contained in, this prospectus and the registration statement of which this prospectus is a part. You should read this prospectus and any applicable prospectus supplement or post-effective amendment to the registration statement of which this prospectus is a part together with the additional information to which we refer you in the sections of this prospectus entitled "Where You Can Find More Information" and "Information Incorporated by Reference."

Because we are a well-known seasoned issuer, as defined in Rule 405 under the Securities Act of 1933 (the "Securities Act"), we may add to and offer additional securities, including secondary securities, by filing a prospectus supplement or term sheet with the SEC.

Unless we state otherwise or the context otherwise requires, the terms "we," "us," "our," "our business" "NioCorp," "the Company" and similar references refer to NioCorp Developments Ltd. and its consolidated subsidiaries.

This prospectus contains our registered and unregistered trademarks and service marks, as well as trademarks and service marks of third parties. Solely for convenience, these trademarks and service marks are referenced without the ®, ™ or similar symbols, but such references are not intended to indicate, in anyway, that we will not assert, to the fullest extent under applicable law, our rights to these trademarks and service marks. All brand names, trademarks and service marks appearing in this prospectus are the property of their respective holders.

Where You Can Find More Information

This prospectus is part of a registration statement on Form S-3 that we filed with the SEC under the Securities Act and does not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement of which this prospectus is a part or the exhibits to the reports or other documents incorporated by reference into this prospectus for a copy of such contract, agreement or other document. You may obtain copies of the registration statement and its exhibits via the SEC's EDGAR database.

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Securities Exchange Act of 1934 (the "Exchange Act"). The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers, including us, that file electronically with the SEC. You may obtain documents that we file with the SEC at www.sec.gov.

We make available, free of charge, on our website at www.niocorp.com, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, proxy statements and amendments to those reports and statements as soon as reasonably practicable after they are filed with the SEC. We do not incorporate the information on or accessible through any website into this prospectus or any prospectus supplement, and you should not consider any information on, or that can be accessed through, any website as part of this prospectus or any prospectus supplement (other than those filings with the SEC that we specifically incorporate by reference into this prospectus or any prospectus supplement). Our website address and the SEC's website address are included in this prospectus as inactive textual references only.

Information Incorporated by Reference

SEC rules permit us to incorporate information by reference into this prospectus and any applicable prospectus supplement. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus and any applicable prospectus supplement, except for information superseded by information contained in this prospectus or the applicable prospectus supplement itself or in any subsequently filed incorporated document. This prospectus and any applicable prospectus supplement incorporate by reference the documents set forth below that we have previously filed with the SEC, other than information in such documents that is deemed to be furnished and not filed. These documents contain important information about us and our business and financial condition. Any report or information within any of the documents referenced below that is furnished, but not filed, shall not be incorporated by reference into this prospectus:

●

our Annual Report on Form 10-K for the fiscal year ended June 30, 2025, filed with the SEC on September 11, 2025;

●

our Current Reports on Form 8-K, filed with the SEC on July 18, 2025, July 23, 2025, August 4, 2025, August 6, 2025, August 12, 2025, September 19, 2025, September 29, 2025 (items 1.01 and 8.01 and related exhibits only) and October 6, 2025; and

●

the description of our Common Shares contained in our Registration Statement on Form 8-A, filed with the SEC on March 17, 2023, as amended by the description of the Common Shares contained in Exhibit 4.37 to our Annual Report on Form 10-K for the fiscal year ended June 30, 2025, filed with the SEC on September 11, 2025, as amended by any subsequently filed amendments and reports filed for the purpose of updating that description.

We also incorporate by reference any future filings made by us with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Exchange Act (excluding any information furnished to, rather than filed with, the SEC), including after the date of the registration statement of which this prospectus is a part and prior to the termination of the offering of securities made by this prospectus. Information in such future filings updates and supplements the information provided in this prospectus. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

You may request a copy of these filings, at no cost, by writing or calling us at the following address or telephone number below:

NioCorp Developments Ltd.
7000 South Yosemite Street, Suite 115
Centennial, Colorado 80112
(720) 334-7066
Attn: Corporate Secretary

Those copies will not include exhibits, unless the exhibits have specifically been incorporated by reference in this document or you specifically request them.

Summary

This summary highlights selected information appearing in this prospectus. Because it is a summary, it may not contain all of the information that may be important to you. To understand this offering fully, you should read this entire prospectus carefully, including the information set forth in the section entitled "Risk Factors" contained in this prospectus and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our consolidated financial statements and related notes and the exhibits to the registration statement of which this prospectus is a part, before making an investment decision. This prospectus includes forward-looking statements that involve risks and uncertainties. See "Cautionary Note Regarding Forward-Looking Statements."

NioCorp Developments Ltd.

NioCorp, through Elk Creek Resources Corp., a Delaware corporation and a majority owned subsidiary of NioCorp, is developing a critical minerals project that, if and when developed, will produce niobium, scandium, titanium, and potentially, rare earth products. Known as the "Elk Creek Project," it is located near Elk Creek, Nebraska, in the southeast portion of the state. Niobium is used to produce various superalloys that are extensively used in high performance aircraft and jet turbines. It also is used in high-strength, low-alloy steel, a stronger steel used in automobiles, bridges, structural systems, buildings, pipelines, and other applications that generally enables those applications to be stronger and lighter in mass. This "lightweighting" benefit often results in environmental benefits, including reduced fuel consumption and material usage, which can result in fewer air emissions. Scandium can be combined with aluminum to make super-high-performance alloys with increased strength and improved corrosion resistance. Scandium also is a critical component of advanced solid oxide fuel cells, an environmentally preferred technology for high-reliability, distributed electricity generation. Titanium is a component of various superalloys and other applications that are used for aerospace applications, weapons systems, protective armor, medical implants and many others. It also is used in pigments for paper, paint, and plastics. Rare earth elements are critical minerals that are needed in virtually all U.S. defense systems and across the electronics, manufacturing, high-technology, transportation, and energy sectors. Magnetic rare earths, such as neodymium, praseodymium, terbium, and dysprosium are critical to the making of neodymium-iron-boron magnets, which are used across a wide variety of defense and civilian applications.

Our primary business strategy is to advance our Elk Creek Project to commercial production. We are focused on carrying out our near-term planned work programs associated with securing the project financing necessary to complete detailed design, development, and construction of the Elk Creek Project, as well as the commencement of early elements of project construction.

Corporate Information

Our Common Shares trade on The Nasdaq Global Market under the symbol "NB." Our principal executive office is located at 7000 South Yosemite Street, Suite 115, Centennial, CO 80112, and our telephone number is (720) 334-7066. Our website address is www.niocorp.com. This website address is not intended to be an active link, and information on, or accessible through, our website is not incorporated by reference into this prospectus and you should not consider any information on, or that can be accessed from, our website as part of this prospectus or any accompanying prospectus supplement.

Risk Factors

Investing in our securities involves a high degree of risk. Prior to making a decision about investing in our securities, you should carefully consider the specific risk factors discussed under the heading "Risk Factors" in our most recent Annual Report on Form 10-K and in our most recent Quarterly Reports on Form 10-Q, which are or will be incorporated herein by reference and may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future. You should also refer to the other information in this prospectus and the applicable prospectus supplement, including our financial statements and the related notes incorporated by reference in this prospectus. The risks and uncertainties we have described are not the only risks we face. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our operations. If any of these risks actually occurs, our business, results of operations and financial condition could suffer and could result in a complete loss of your investment.

Cautionary Note Regarding Forward-Looking Statements

This prospectus and the other documents incorporated by reference into this prospectus contain or may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act, and "forward-looking information" within the meaning of applicable Canadian securities legislation (collectively, "forward-looking statements"). Such forward-looking statements concern our anticipated results and developments in the operations of the Company in future periods, planned exploration activities, the adequacy of the Company's financial resources, and other events or conditions that may occur in the future.

Forward-looking statements have been based upon our current business and operating plans, as approved by the Company's Board of Directors, and may include statements regarding, among other matters, the financial and business performance of NioCorp; NioCorp's anticipated results and developments in the operations of NioCorp in future periods; NioCorp's planned exploration activities; the adequacy of NioCorp's financial resources; NioCorp's ability to secure sufficient project financing to complete construction and commence operation of the Elk Creek Project; NioCorp's ability to receive a final commitment of financing from the Export-Import Bank of the United States ("EXIM"); the estimated total upfront capital expenditure for the Elk Creek Project; NioCorp's expectation and ability to produce niobium, scandium, and titanium and the potential to produce rare earth elements at the Elk Creek Project; NioCorp's plans to produce and supply specific products and market demand for those products; NioCorp's ability to access the full amount of the expected net proceeds of the Standby Equity Purchase Agreement, dated January 26, 2023 (as amended, the "Yorkville Equity Facility Financing Agreement"), between NioCorp and YA II PN, Ltd., a fund managed by Yorkville Advisors Global, LP, through April 1, 2026; NioCorp's expectation that it will receive the full $10 million in reimbursement under the Project Sub-Agreement with Advanced Technology International, an entity acting on behalf of the Defense Industrial Base Consortium under the authority of the U.S. Department of Defense (the "DoD Agreement"); the intended use of our cash balance as of June 30, 2025, as well as the proceeds from the Company's registered public offering that closed on July 18, 2025, the proceeds from Warrant exercise issuances, and the reimbursement payments pursuant to the DoD Agreement; the expected results of the drilling program at the Elk Creek Project; the expectation that the results of the drilling program will be used to update the feasibility study for the Elk Creek Project; the Elk Creek Project's ability to produce multiple critical metals; the Elk Creek Project's projected ore production and mining operations over its expected mine life; the completion of technical and economic analyses on the potential addition of magnetic rare earth oxides to NioCorp's planned product suite; statements with respect to the estimation of mineral resources and mineral reserves; the exercise of options to purchase additional land parcels; the execution of contracts with engineering, procurement and construction companies; NioCorp's ongoing evaluation of the impact of inflation, supply chain issues, tariffs, and geopolitical unrest on the Elk Creek Project's economic model; and the creation of full time and contract construction jobs over the construction period of the Elk Creek Project.

Forward-looking statements are frequently, but not always, identified by words such as "expects," "anticipates," "believes," "intends," "estimates," "potential," "possible," and similar expressions, or statements that events, conditions, or results "will," "may," "could," or "should" (or the negative and grammatical variations of any of these terms) occur or be achieved. Any statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, or future events or performance (often, but not always, using words or phrases such as "expects" or "does not expect," "is expected," "anticipates" or "does not anticipate," "plans," "estimates," or "intends," or stating that certain actions, events, or results "may," "could," "would," "might," or "will" be taken, occur or be achieved) are not statements of historical fact and may be forward-looking statements. Forward-looking statements reflect material expectations and assumptions, including, without limitation, expectations and assumptions relating to: NioCorp's ability to receive sufficient project financing for the construction of the Elk Creek Project on acceptable terms, or at all; the future price of metals; the stability of the financial and capital markets; and current estimates and assumptions regarding the Yorkville Equity Facility Financing Agreement and its benefits. Such forward-looking statements reflect the Company's current views with respect to future events and are subject to certain known and unknown risks, uncertainties, and assumptions. Many factors could cause actual results, performance, or achievements to be materially different from any future results, performance, or achievements that may be expressed or implied by such forward-looking statements, including, among others, risks related to the following: NioCorp's ability to operate as a going concern; NioCorp's requirement of significant additional capital; NioCorp's ability to receive sufficient project financing for the construction of the Elk Creek Project on acceptable terms, or at all; NioCorp's ability to achieve the required milestones and receive the full $10.0 million in reimbursement under the DoD Agreement; NioCorp's ability to receive a final commitment of financing from EXIM or other debt financing or financial support on acceptable timelines, on acceptable terms, or at all; NioCorp's ability to access the full amount of the expected net proceeds under the Yorkville Equity Facility Financing Agreement; NioCorp's ability to continue to meet the listing standards of The Nasdaq Stock Market LLC ("Nasdaq"); risks relating to the Common Shares, including price volatility, lack of dividend payments and dilution or the perception of the likelihood of any of the foregoing; the extent to which NioCorp's level of indebtedness and/or the terms contained in agreements governing NioCorp's indebtedness, if any, the Yorkville Equity Facility Financing Agreement or other agreements may

impair NioCorp's ability to obtain additional financing, on acceptable terms, or at all; covenants contained in agreements with NioCorp's secured creditors that may affect its assets; NioCorp's limited operating history; NioCorp's history of losses; the material weaknesses in NioCorp's internal control over financial reporting, NioCorp's efforts to remediate such material weaknesses and the timing of remediation; the possibility that NioCorp may qualify as a PFIC under the U.S. Internal Revenue Code of 1986, as amended (the "Code"); the potential that the transactions contemplated by the Business Combination Agreement (as defined herein) that closed in March 2023, including, among others, the GXII Transaction (as defined herein) and the entry into the Yorkville Equity Facility Financing Agreement, could result in NioCorp becoming subject to materially adverse U.S. federal income tax consequences as a result of the application of Section 7874 and related sections of the Code; cost increases for NioCorp's exploration and, if warranted, development projects; a disruption in, or failure of, NioCorp's information technology systems, including those related to cybersecurity; equipment and supply shortages; variations in the market demand for, and prices of, niobium, scandium, titanium and rare earth products; current and future offtake agreements, joint ventures, and partnerships, including our ability to negotiate extensions to existing agreements or to enter into new agreements, on favorable terms or at all; NioCorp's ability to attract qualified management; estimates of mineral resources and reserves; mineral exploration and production activities; feasibility study results; the results of metallurgical testing; the results of technological research; changes in demand for and price of commodities (such as fuel and electricity) and currencies; competition in the mining industry; changes or disruptions in the securities markets; legislative, political or economic developments, including changes in federal and/or state laws that may significantly affect the mining industry; trade policies and tensions, including tariffs; inflationary pressures; the impacts of climate change, as well as actions taken or required by governments related to strengthening resilience in the face of potential impacts from climate change; the need to obtain permits and comply with laws and regulations and other regulatory requirements; the timing and reliability of sampling and assay data; the possibility that actual results of work may differ from projections/expectations or may not realize the perceived potential of NioCorp's projects; risks of accidents, equipment breakdowns, and labor disputes or other unanticipated difficulties or interruptions; the possibility of cost overruns or unanticipated expenses in development programs; operating or technical difficulties in connection with exploration, mining, or development activities; management of the water balance at the Elk Creek Project site; land reclamation requirements related to the Elk Creek Project; the speculative nature of mineral exploration and development, including the risks of diminishing quantities of grades of reserves and resources; claims on the title to NioCorp's properties; potential future litigation; and NioCorp's lack of insurance covering all of NioCorp's operations.

Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described herein. This list is not exhaustive of the factors that may affect any of the Company's forward-looking statements. Forward-looking statements are statements about the future and are inherently uncertain, and actual achievements of the Company or other future events or conditions may differ materially from those reflected in the forward-looking statements due to a variety of risks, uncertainties, and other factors, including without limitation those discussed in this prospectus under the heading "Risk Factors" and under Part I, Item 1A. "Risk Factors" contained in our most recent Annual Report on Form 10-K, and Part II, Item 1A. "Risk Factors" contained in our subsequent Quarterly Reports on Form 10-Q, as well as any amendments thereto, which are incorporated by reference into this prospectus and the applicable prospectus supplement in their entirety, together with other information in this prospectus and the applicable prospectus supplement and the documents incorporated by reference herein and therein. See the sections of this prospectus entitled "Where You Can Find More Information" and "Information Incorporated by Reference."

The Company's forward-looking statements contained in this prospectus are based on the beliefs, expectations, and opinions of management as of the date of this prospectus. The Company does not assume any obligation to update forward-looking statements if circumstances or management's beliefs, expectations, or opinions should change, except as required by law. For the reasons set forth above, investors should not attribute undue certainty to, or place undue reliance on, forward-looking statements.

Use of Proceeds

Unless the applicable prospectus supplement states otherwise, we expect to use the net proceeds of the sale of the securities offered by this prospectus for working capital and general corporate purposes, including to advance our efforts to launch construction of the Elk Creek Project and move it to commercial operation.

As of the date of this prospectus, we have not identified as probable any specific material proposed uses of these proceeds. If, as of the date of any prospectus supplement, we have identified any such uses, we will describe them in the prospectus supplement. Pending any such uses, we may temporarily invest the net proceeds in liquid assets that may include money market funds and guaranteed obligations of the U.S. government.

Description of Capital Stock

Common Shares

The authorized capital of the Company consists of an unlimited number of Common Shares without par value, of which 101,568,807 were issued and outstanding as of October 9, 2025. The holders of Common Shares are entitled to receive notice of and attend all meetings of shareholders, with each Common Share held entitling the holder to one (1) vote on any resolution to be passed at such shareholder meetings. The holders of Common Shares are entitled to dividends if, as and when declared by the Company's Board of Directors. The Common Shares are entitled, upon liquidation, dissolution, or winding up of the Company, to receive the remaining assets of the Company available for distribution to shareholders. There are no pre-emptive, conversion, or redemption rights attached to the Common Shares.

Exchange Controls

There are no governmental laws, decrees, or regulations in Canada that restrict the export or import of capital, including foreign exchange controls, or that affect the remittance of dividends, interest or other payments to non-resident holders of the securities of the Company, other than as discussed below and Canadian withholding tax. See "-Certain Canadian Federal Income Tax Considerations for U.S. Residents."

Certain Canadian Federal Income Tax Considerations for U.S. Residents

The following generally summarizes certain Canadian federal income tax consequences generally applicable under the Income Tax Act (Canada) and the regulations enacted thereunder (collectively, the "Canadian Tax Act") and the Canada-United States Tax Convention (1980) (the "Convention") to the holding and disposition of Common Shares.

Comment is restricted to holders of Common Shares each of whom, at all material times for the purposes of the Canadian Tax Act and the Convention, (i) is resident solely in the U.S. for tax purposes, (ii) is a "qualifying person" under and entitled to the benefits of the Convention, (iii) holds all Common Shares as capital property, (iv) deals at arm's length with and is not affiliated with the Company, (v) does not and is not deemed to use or hold any Common Shares in a business carried on in Canada, (vi) is not an insurer that carries on business in Canada and elsewhere, (vii) is not an "authorized foreign bank" (as defined in the Canadian Tax Act), and (viii) has not entered into a "derivative forward agreement", "synthetic equity arrangement" or "synthetic disposition arrangement" (each as defined in the Canadian Tax Act) with respect to the Common Shares (each such holder, a "U.S. Resident Holder").

Certain U.S.-resident entities that are fiscally transparent for U.S. federal income tax purposes (including limited liability companies) may not in all circumstances be entitled to the benefits of the Convention. Members of or holders of an interest in such an entity that holds Common Shares should consult their own tax advisers regarding the extent, if any, to which the benefits of the Convention will apply to the entity in respect of its Common Shares.

Generally, a U.S. Resident Holder's Common Shares will be considered to be capital property of such holder provided that the U.S. Resident Holder is not a trader or dealer in securities, did not acquire, hold, or dispose of the Common Shares in one or more transactions considered to be an adventure or concern in the nature of trade (i.e., speculation), and does not hold the Common Shares in the course of carrying on a business.

This summary is based on the current provisions of the Canadian Tax Act and the Convention in effect as of the date prior to the date hereof, all specific proposals to amend the Canadian Tax Act and the Convention publicly announced by or on behalf of the Minister of Finance (Canada) prior to the date hereof, and the current published administrative policies and assessing practices of the Canada Revenue Agency (the "CRA"). It is assumed that all such amendments will be enacted as currently proposed, and that there will be no other material change to any applicable law or administrative policy or assessing practice, whether by way of judicial, legislative or governmental decision or action, although no assurance can be given in these respects. Except as otherwise expressly provided, this summary does not take into account any provincial, territorial, or foreign tax considerations, which may differ materially from those set out herein.

This summary is of a general nature only, is not exhaustive of all possible Canadian federal income tax considerations, and is not intended to be and should not be construed as legal or tax advice to any particular U.S. Resident Holder. The tax consequences of holding and disposing of Common Shares will vary according to the U.S. Resident Holder's particular circumstances. U.S. Resident Holders are urged to consult their own tax advisers for advice with respect to their particular circumstances. The discussion below is qualified accordingly.

A U.S. Resident Holder who disposes or is deemed to dispose of one or more Common Shares generally should not incur any liability for Canadian federal income tax in respect of any capital gain arising as a consequence of the disposition, unless the Common Shares constitute "taxable Canadian property" (as defined in the Canadian Tax Act) of the U.S. Resident Holder at the time of disposition and the U.S. Resident Holder is not entitled to relief under the Convention.

Generally, a U.S. Resident Holder's Common Shares will not constitute "taxable Canadian property" of such holder at a particular time at which the Common Shares are listed on a "designated stock exchange" (which currently includes Nasdaq) unless at any time during the 60-month period that ends at the particular time both of the following conditions are concurrently met:

(i)

25% or more of the issued shares of any class of the capital stock of the Company were owned by or belonged to one or any combination of:

(A)

the U.S. Resident Holder,

(B)

persons with whom the U.S. Resident Holder did not deal at arm's length, and

(C)

partnerships in which the U.S. Resident Holder or a person referred to in clause (B) holds a membership interest directly or indirectly through one or more partnerships, and

(ii)

more than 50% of the fair market value of the Common Shares was derived directly or indirectly from, one or any combination of, real or immovable property situated in Canada, "Canadian resource properties" (as defined in the Canadian Tax Act), "timber resource properties" (as defined in the Canadian Tax Act), or options in respect of, or interests in, or for civil law rights in, any of the foregoing, whether or not the property exists.

Notwithstanding the foregoing, Common Shares may also be deemed to be "taxable Canadian property" in certain circumstances set out in the Canadian Tax Act.

A U.S. Resident Holder to whom the Company pays or credits or is deemed to pay or credit a dividend on such holder's Common Shares will be subject to Canadian withholding tax, and the Company will be required to withhold the tax from the dividend and remit it to the CRA for the holder's account. The rate of withholding tax under the Canadian Tax Act is 25% of the gross amount of the dividend, but should generally be reduced under the Convention to 15% (or, if the U.S. Resident Holder is a company which is the beneficial owner of at least 10% of the voting stock of the Company, 5%) of the gross amount of the dividend. For this purpose, a company that is a resident of the U.S. for purposes of the Canadian Tax Act and the Convention and is entitled to the benefits of the Convention shall be considered to own the voting stock of the Company owned by an entity that is considered fiscally transparent under the laws of the U.S. and that is not a resident of Canada, in proportion to such company's ownership interest in that entity.

Competition Act

Limitations on the ability to acquire and hold Common Shares may be imposed by the Competition Act (Canada). This legislation permits the Commissioner of Competition of Canada (the "Commissioner") to review any acquisition of a significant interest in the Company. This legislation grants the Commissioner jurisdiction to challenge such an acquisition before the Canadian Competition Tribunal if the Commissioner believes that it would, or would be likely to, result in a substantial lessening or prevention of competition in any market in Canada.

Investment Canada Act

The Investment Canada Act subjects an acquisition of control of a Canadian business by a non-Canadian to government notification or review depending on whether the relevant financial threshold (based on enterprise value or asset value of the company), as calculated pursuant to the legislation, exceeds a threshold amount. A reviewable acquisition may not proceed unless the relevant minister is satisfied that the investment is likely to result in a net benefit to Canada. Under the national-security-review regime in the Investment Canada Act, review on a discretionary basis may also be undertaken by the federal government in respect of a broad range of investments by a non-Canadian. No financial threshold applies to a national security review. The relevant test is whether such investment by a non-Canadian could be "injurious to national security."

Warrants

From time to time, the Company has outstanding Warrants, with each whole Warrant exercisable for one Common Share. The exercise price per Common Share and the number of Common Shares issuable upon exercise of Warrants is subject to adjustment upon the occurrence of certain events, including, but not limited to, the following:

●

the subdivision or re-division of the outstanding Common Shares into a greater number of Common Shares;

●

the reduction, combination or consolidation of the outstanding Common Shares into a lesser number of Common Shares;

●

the issuance of Common Shares or securities exchangeable for, or convertible into, Common Shares to all or substantially all of the holders of Common Shares by way of stock dividend or other distribution (other than a distribution of Common Shares upon the exercise of Warrants or any outstanding options);

●

the reorganization of the Company or the consolidation or merger or amalgamation of the Company with or into another corporate body; and

●

a reclassification or other similar change to the outstanding Common Shares.

The Company generally will issue the Common Shares issuable upon exercise of Warrants within five business days following its receipt of notice of exercise and payment of the exercise price, subject to surrender of the Warrants. Prior to the exercise of any Warrants, holders of the Warrants will not have any of the rights of holders of the Common Shares issuable upon exercise, including the right to vote or to receive any payments of dividends on the Common Shares issuable upon exercise. See "Description of Warrants" for additional information regarding Warrants that may be issued pursuant to this prospectus.

NioCorp Assumed Warrants

On March 17, 2023 (the "Closing Date"), the Company closed a series of transactions (the "GXII Transaction") pursuant to the Business Combination Agreement, dated as of September 25, 2022 (the "Business Combination Agreement"), by and among the Company, GX Acquisition Corp. II, a Delaware corporation ("GXII"), and Big Red Merger Sub Ltd., a Delaware corporation and a direct, wholly owned subsidiary of the Company. In connection with the closing of the GXII Transaction (the "Closing"), pursuant to the Business Combination Agreement, the Company assumed GXII's obligations under the Warrant Agreement, dated March 17, 2021 (the "GXII Warrant Agreement"), by and between GXII and Continental Stock Transfer & Trust Company ("CST"), as warrant agent, and each share purchase warrant of GXII thereunder (the "GXII Warrants") that was issued and outstanding immediately prior to the Closing Date was converted into one Warrant (the "NioCorp Assumed Warrants") pursuant to the GXII Warrant Agreement, as amended by an Assignment, Assumption and Amendment Agreement, dated the Closing Date (the GXII Warrant Agreement, as so amended, the "NioCorp Assumed Warrant Agreement"), among the Company, GXII, CST, as existing warrant agent, and Computershare Inc. and its affiliate Computershare Trust Company, N.A, together as successor warrant agent (the "NioCorp Assumed Warrant Agent"). In connection with the Closing, NioCorp issued (a) 9,999,959 public NioCorp Assumed Warrants in respect of the GXII Warrants that were publicly traded prior to the Closing and (b) 5,666,667 NioCorp Assumed Warrants to GX Sponsor II LLC (the "Sponsor") in respect of the GXII Warrants that it held prior to the Closing, which NioCorp Assumed Warrants were subsequently distributed by the Sponsor to its members in connection with the Closing.

Both the public NioCorp Assumed Warrants and the NioCorp Assumed Warrants issued to the Sponsor are subject to the terms of the NioCorp Assumed Warrant Agreement and are identical, with certain exceptions applicable to the NioCorp Assumed Warrants issued to the Sponsor for so long as such NioCorp Assumed Warrants are held by the Sponsor, its members, or their respective affiliates and other permitted transferees. In accordance with the NioCorp Assumed Warrant Agreement, any NioCorp Assumed Warrants issued to the Sponsor that are held by someone other than the Sponsor, its members, or their respective affiliates and other permitted transferees, are treated as public NioCorp Assumed Warrants.

Each NioCorp Assumed Warrant is exercisable on and after April 16, 2023 until its expiration for 1.11829212 Common Shares at a price of $11.50 per 1.11829212 Common Shares (subject to adjustments for stock splits, stock dividends, reorganizations, recapitalizations and the like). Under the terms of NioCorp Assumed Warrant Agreement, for so long as the NioCorp Assumed Warrants issued to the Sponsor are held by the Sponsor, its members, or their respective affiliates and other permitted transferees, such holders have the right to elect to exercise those NioCorp Assumed Warrants on a cashless basis. For such NioCorp Assumed Warrants exercised on a cashless basis after the Closing, the holder will be entitled to pay the exercise price for those NioCorp Assumed Warrants by surrendering all or portion of the cash and/or Common Shares (valued at their fair market value) into which those

NioCorp Assumed Warrants are exercisable as shall be elected by the holder. For this purpose, Common Shares so surrendered will be deemed to have a "fair market value" equal to the average reported last sale price of the Common Shares for the 10 trading days ending on the third trading day prior to the date of exercise of the applicable NioCorp Assumed Warrants.

The NioCorp Assumed Warrants will expire at 5:00 p.m., New York City time, on March 17, 2028 or earlier upon redemption or liquidation.

The Company will not be obligated to deliver any Common Shares pursuant to the exercise of a NioCorp Assumed Warrant and will have no obligation to settle such exercise unless a registration statement under the Securities Act with respect to the Common Shares underlying the NioCorp Assumed Warrants is then effective and a prospectus relating thereto is current, subject to the Company satisfying its obligations described below with respect to registration. No NioCorp Assumed Warrant will be exercisable and the Company will not be obligated to issue Common Shares upon exercise of a NioCorp Assumed Warrant unless Common Shares issuable upon such exercise have been registered, qualified or deemed to be exempt under the securities laws of the state of residence of the registered holder of the NioCorp Assumed Warrants. In the event that the conditions in the two immediately preceding sentences are not satisfied with respect to a NioCorp Assumed Warrant, the holder of such NioCorp Assumed Warrant will not be entitled to exercise such NioCorp Assumed Warrant and such NioCorp Assumed Warrant may have no value and expire worthless. In no event will the Company be required to net cash settle any NioCorp Assumed Warrant.

The NioCorp Assumed Warrants, and the underlying Common Shares issuable upon the exercise thereof, were registered under the Securities Act pursuant to the Company's registration statement on Form S-4, originally filed on November 7, 2022, as subsequently amended, which was declared effective by the SEC on February 8, 2023. The ongoing registered offering of the Common Shares underlying the NioCorp Assumed Warrants is being conducted pursuant to the Company's registration statement on Form S-3, originally filed on April 14, 2023, as subsequently post-effectively amended to convert such registration statement to Form S-1, which was declared effective on October 30, 2023.

The Company will have the right to call the public NioCorp Assumed Warrants for redemption at any time following the Closing Date:

●

in whole and not in part;

●

at a price of $0.01 per NioCorp Assumed Warrant;

●

upon not less than 30 days' prior written notice of redemption (the "30-day redemption period") to each public NioCorp Assumed Warrant holder;

●

if, and only if, the reported last sale price of the Common Shares equals or exceeds approximately $16.10 per share (subject to certain adjustments) for any 20 trading days within a 30-trading day period commencing once the NioCorp Assumed Warrants become exercisable and ending three business days before the Company sends the notice of redemption to the public NioCorp Assumed Warrant holders; and

●

if there is an effective registration statement covering the Common Shares issuable upon exercise of the NioCorp Assumed Warrants, and a current prospectus relating thereto, available throughout the 30-day redemption period.

The NioCorp Assumed Warrants issued to the Sponsor are not redeemable by the Company for so long as such NioCorp Assumed Warrants are held by the Sponsor, its members, or their respective affiliates or other permitted transferees. In addition, the Company may not exercise its redemption right if the issuance of Common Shares upon exercise of the NioCorp Assumed Warrants is not exempt from registration or qualification under applicable state blue sky laws or the Company is unable to effect such registration or qualification.

If the Company calls the public NioCorp Assumed Warrants for redemption as described above, the Company will have the option to require any holder that wishes to exercise its public NioCorp Assumed Warrant to do so on a "cashless basis." In determining whether to require all holders to exercise their public NioCorp Assumed Warrants on a "cashless basis," the Company will consider, among other factors, its cash position, the number of NioCorp Assumed Warrants that are outstanding and the dilutive effect on the Company's shareholders of issuing the maximum number of Common Shares issuable upon the exercise of the NioCorp Assumed Warrants. If the Company takes advantage of this option, all holders of public NioCorp Assumed Warrants would pay the exercise price by surrendering their NioCorp Assumed Warrants for that number of Common Shares equal to the quotient obtained by dividing (x) the product of the number of Common Shares underlying the public NioCorp Assumed Warrants, multiplied by the

difference between the exercise price of the NioCorp Assumed Warrants and the "fair market value" (defined below) by (y) the fair market value. The "fair market value" shall mean the average reported last sale price of the Common Shares for the 10 trading days ending on the third trading day prior to the date on which the notice of redemption is sent to the holders of public NioCorp Assumed Warrants. If the Company takes advantage of this option, the notice of redemption will contain the information necessary to calculate the number of Common Shares to be received upon exercise of the NioCorp Assumed Warrants, including the "fair market value" in such case. Requiring a cashless exercise in this manner will reduce the number of Common Shares to be issued and thereby lessen the dilutive effect of a redemption of the public NioCorp Assumed Warrants. If the Company calls the public NioCorp Assumed Warrants for redemption and does not take advantage of this option, the Sponsor, its members, and their respective affiliates and other permitted transferees would still be entitled to exercise their NioCorp Assumed Warrants for cash or on a cashless basis using the same formula described above that other NioCorp Assumed Warrant holders would have been required to use had all NioCorp Assumed Warrant holders been required to exercise their NioCorp Assumed Warrants on a cashless basis, as described in more detail below.

A holder of a NioCorp Assumed Warrant may notify the Company in writing in the event it elects to be subject to a requirement that such holder will not have the right to exercise such NioCorp Assumed Warrant, to the extent that after giving effect to such exercise, such holder (together with such holder's affiliates), to the NioCorp Assumed Warrant Agent's actual knowledge, would beneficially own in excess of 4.9% or 9.8% (or such other amount as a holder may specify) of the Common Shares outstanding immediately after giving effect to such exercise.

The NioCorp Assumed Warrants have certain anti-dilution and adjustments rights upon certain events.

The NioCorp Assumed Warrants may be exercised upon surrender of the certificate representing such NioCorp Assumed Warrants on or prior to the expiration date at the offices of the NioCorp Assumed Warrant Agent, with the exercise form on the reverse side of such certificate completed and executed as indicated, accompanied by full payment of the exercise price (or on a cashless basis, if applicable), by certified or official bank check payable to the order of the NioCorp Assumed Warrant Agent or by wire transfer, for the number of NioCorp Assumed Warrants being exercised. The NioCorp Assumed Warrant holders will not have the rights or privileges of holders of Common Shares or any attendant voting rights until they exercise their NioCorp Assumed Warrants and receive Common Shares. After the issuance of Common Shares upon exercise of the NioCorp Assumed Warrants, each holder will be entitled to one (1) vote for each Common Share held of record on all matters to be voted on by NioCorp shareholders.

If, upon exercise of the NioCorp Assumed Warrants, a holder would be entitled to receive a fractional interest in a share, the Company will, upon exercise, round down to the nearest whole number of Common Shares to be issued to the NioCorp Assumed Warrant holder.

The NioCorp Assumed Warrants were issued in registered form under the NioCorp Assumed Warrant Agreement. The NioCorp Assumed Warrant Agreement may be amended by the parties thereto without the consent of any registered holder (i) for the purpose of curing any ambiguity, or curing, correcting or supplementing any mistake, or adding or changing any other provisions with respect to matters or questions arising under NioCorp Assumed Warrant Agreement as the parties may deem necessary or desirable and that the parties deem shall not adversely affect the interest of the registered holders of the NioCorp Assumed Warrants, and (ii) to provide for the delivery of such kind and amount of Common Shares or other securities or property (including cash) receivable upon a reclassification, reorganization, merger or consolidation, or upon a dissolution following any such sale or transfer, that the holder of NioCorp Assumed Warrants would have received if such holder had exercised his, her or its NioCorp Assumed Warrants immediately prior to such event. All other modifications or amendments, including any amendment to increase the warrant price or shorten the exercise period, shall require the vote or written consent of the registered holders of a majority of the then outstanding public NioCorp Assumed Warrants. Any amendment solely to the NioCorp Assumed Warrants issued to the Sponsor and that are held by the Sponsor, its members, or their respective affiliates or other permitted transferees, shall require the vote or written consent of a majority of the holders of the then outstanding NioCorp Assumed Warrants issued to the Sponsor.

Description of Warrants

General

The following description, together with the additional information we may include in any applicable prospectus supplement, summarizes the material terms and provisions of the Warrants that we may offer under this prospectus. While the terms we have summarized below will apply generally to any Warrants that we may offer under this prospectus, we will describe the particular terms of any series of Warrants in more detail in the applicable prospectus supplement. The terms of any Warrants offered under a prospectus supplement may differ from the terms described below.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from another report that we file with the SEC, the form of Warrant agreement or Warrant indenture, which may include a form of Warrant certificate, that describes the terms of the particular series of Warrants we are offering before the issuance of the related series of Warrants. The following summary of material provisions of the Warrants and the Warrant agreements and the Warrant indentures are subject to, and qualified in their entirety by reference to, all the provisions of the Warrant agreement or Warrant indenture, and Warrant certificate, applicable to a particular series of Warrants. We urge you to read the applicable prospectus supplement related to the particular series of Warrants that we sell under this prospectus, as well as the complete Warrant agreements, Warrant indentures and Warrant certificates that contain the terms of the Warrants.

We will describe in the applicable prospectus supplement the terms relating to Warrants being offered including:

●

the offering price and aggregate number of Warrants offered;

●

if applicable, the number of Warrants issued with each Common Share being issued;

●

if applicable, the date on and after which the Warrants and the related Common Shares will be separately transferable;

●

the number of Common Shares purchasable upon exercise of one Warrant and the price at which these Common Shares may be purchased upon such exercise;

●

the terms of any rights to redeem or call the Warrants;

●

any provisions for changes to or adjustments in the exercise price or number of Common Shares issuable upon exercise of the Warrants;

●

the dates on which the right to exercise the Warrants will commence and expire;

●

the manner in which the Warrant agreements, Warrant indentures and Warrants may be modified;

●

federal income tax consequences of holding or exercising the Warrants, if material; and

●

any other specific terms, preferences, rights or limitations of or restrictions on the Warrants.

Before exercising their Warrants, holders of Warrants will not have any of the rights of holders of the Common Shares purchasable upon such exercise, including the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up of our affairs or to exercise voting rights, if any.

Exercise of Warrants

Unless we otherwise specify in the applicable prospectus supplement, each Warrant will entitle the holder to purchase one Common Share at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the Warrants may exercise the Warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement, and after the close of business on the expiration date, unexercised Warrants will become void.

Holders of the Warrants may exercise the Warrants by delivering the Warrant certificate representing the Warrants to be exercised together with specified information, and paying the required amount to the Warrant agent in immediately available funds, as provided

in the applicable prospectus supplement. We intend to set forth in any Warrant agreement or Warrant indenture and in the applicable prospectus supplement the information that the holder of the Warrant will be required to deliver to the Warrant agent.

Upon receipt of the required payment and any Warrant certificate or other form required for exercise properly completed and duly executed at the corporate trust office of the Warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the Common Shares purchasable upon such exercise. If fewer than all of the Warrants represented by the Warrant or Warrant certificate are exercised, then we will issue a new Warrant or Warrant certificate for the remaining amount of Warrants. If we so indicate in the applicable prospectus supplement, holders of the Warrants may surrender securities as all or part of the exercise price for Warrants.

Description of Debt Securities

The following description sets forth certain general terms and provisions of the debt securities that we may issue, which may be issued as convertible or exchangeable debt securities. We will set forth the particular terms of the debt securities we offer in a prospectus supplement and the extent, if any, to which the following general terms and provisions will apply to particular debt securities.

The debt securities will be issued under an indenture to be entered into between us and a trustee to be named in a prospectus supplement. The indenture, and any supplemental indentures thereto, will be subject to, and governed by, the Trust Indenture Act of 1939. The following description of general terms and provisions relating to the debt securities and the indenture under which the debt securities will be issued is a summary only and therefore is not complete and is subject to, and qualified in its entirety by reference to, the terms and provisions of the indenture. The form of the indenture has been filed with the SEC as an exhibit to the registration statement of which this prospectus forms a part and you should read the indenture for provisions that may be important to you. For more information on how you can obtain a copy of the form of the indenture, see "Where You Can Find More Information."

Capitalized terms used in this section and not defined herein have the meanings specified in the indenture. When we refer to "NioCorp," "we," "our" and "us" in this section, we mean NioCorp Developments Ltd. excluding, unless the context otherwise requires or as otherwise expressly stated, its subsidiaries.

General

Unless otherwise specified in a prospectus supplement, the debt securities will be our direct, unsecured obligations and will rank equally with all of our future senior unsecured indebtedness and senior in right of payment to all of our subordinated indebtedness.

The indenture will not limit the aggregate principal amount of debt securities that may be issued under it and will provide that debt securities may be issued under it from time to time in one or more series. We may specify a maximum aggregate principal amount for the debt securities of any series.

Unless otherwise specified in the applicable prospectus supplement, the indenture will not afford the holders of the debt securities the right to require us to repurchase or redeem the debt securities in the event of a highly-leveraged transaction.

We will not be obligated to issue all debt securities of one series at the same time and, unless otherwise provided in the applicable prospectus supplement, we may reopen a series, without the consent of the holders of the outstanding debt securities of that series, for the issuance of additional debt securities of that series. Additional debt securities of a particular series will have the same terms and conditions as outstanding debt securities of such series, except for the issue date and, in some cases, the public offering price and the first interest payment date, and will be consolidated with, and form a single series with, such outstanding debt securities; provided, however, that if such additional debt securities are not fungible with the outstanding debt securities of such series for U.S. federal income tax purposes, the additional debt securities will have a separate CUSIP number.

We will set forth in a prospectus supplement relating to any debt securities being offered, the aggregate principal amount and the following terms of the debt securities, if applicable:

●

the title of the series of debt securities;

●

the price or prices (expressed as a percentage of the principal amount) at which the debt securities will be issued;

●

any limit on the aggregate principal amount of the series of debt securities;

●

whether the debt securities will be senior debt securities or subordinated debt securities, and if they are subordinated debt securities, the terms of the subordination;

●

the date or dates on which the principal of the series of debt securities is payable;

●

the rate or rates (which may be fixed or variable) per annum or the method used to determine such rate or rates (including any commodity, commodity index, stock exchange index or financial index) at which the series of debt securities will bear interest, if any, the date or dates from which such interest, if any, will accrue, the date or dates on which such interest, if any, will commence and be payable and any regular record date for the interest payable on any interest payment date;

●

the right, if any to extend the interest periods and the duration of that extension;

●

the place or places where the principal of, and premium and interest, if any, on, the debt securities will be payable;

●

the terms and conditions upon which the debt securities may be redeemed;

●

any obligation we may have to redeem or purchase the debt securities pursuant to any sinking fund or analogous provisions or at the option of a holder of the debt securities;

●

the dates on which and the price or prices at which we will repurchase the debt securities at the option of the holders of the debt securities and other detailed terms and provisions of such repurchase obligations;

●

the denominations in which the debt securities will be issued, if other than denominations of $2,000 and integral multiples of $1,000 in excess thereof;

●

whether the debt securities will be issued in the form of certificated debt securities or global debt securities;

●

the portion of principal amount of the debt securities payable upon declaration of acceleration of the maturity date, if other than the principal amount;

●

the designation of the currency, currencies or currency units in which payment of principal of, premium and interest, if any, on the debt securities will be made if other than U.S. dollars;

●

any provisions relating to any security provided for the debt securities;

●

any addition to or change in the events of default described in this prospectus or in the indenture and any change in the acceleration provisions described in this prospectus or in the indenture with respect to the debt securities;

●

any addition to or change in the covenants described in this prospectus or in the indenture with respect to the debt securities;

●

any other terms of the debt securities (which may supplement, modify or delete any provision of the indenture as it applies to such debt securities);

●

any depositaries, interest rate calculation agents, exchange rate calculation agents or other agents with respect to the series of debt securities, if other than appointed in the indenture; and

●

any provisions relating to conversion of the debt securities.

The foregoing is not intended to be an exclusive list of the terms that may be applicable to any offered debt securities.

In addition, the indenture will not limit our ability to issue convertible, exchangeable or subordinated debt securities. Any conversion, exchange or subordination provisions of debt securities will be described in the relevant prospectus supplement. Such terms may include provisions for conversion or exchange, either mandatory, at the option of the holder or at our option, in which case the number of Common Shares or other securities to be received by the holders of debt securities would be calculated as of a time and in the manner stated in the prospectus supplement.

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on U.S. and Canadian federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a currency or currencies or a currency unit or units other than U.S. dollars, or if the principal of and any premium and interest on any series of debt securities is payable in a currency or currencies or a currency unit or units other than U.S. dollars, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such currency or currencies or currency unit or units in the applicable prospectus supplement.

Exchange and Transfer

Debt securities may be transferred or exchanged at the office of the registrar or co-registrar designated by us.

We will not impose a service charge for any transfer or exchange, but we may require holders to pay any tax or other governmental charges associated with any transfer or exchange.

In the event of any redemption of debt securities of any series, we will not be required to:

●

issue, register the transfer of, or exchange, any debt security of that series during a period beginning at the opening of 15 business days before the day of sending of a notice of redemption and ending at the close of business on the day such notice is sent; or

●

register the transfer of, or exchange, any debt security of that series selected, called or being called for redemption, in whole or in part, except the unredeemed portion of any series being redeemed in part.

We may initially appoint the trustee as the registrar. Any transfer agent, in addition to the registrar initially designated by us, will be named in the prospectus supplement. We may designate additional transfer agents or change transfer agents or change the office of the transfer agent. However, we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

Global Securities

The debt securities of any series may be represented, in whole or in part, by one or more global securities. Each global security will:

●

be registered in the name of a depositary that we will identify in a prospectus supplement;

●

be deposited with the trustee as custodian for the depositary or its nominee; and

●

bear any required legends.

No global security may be exchanged in whole or in part for debt securities registered in the name of any person other than the depositary or any nominee unless:

●

the depositary has notified us that it is unwilling or unable to continue as depositary or has ceased to be qualified to act as depositary, and in either case we fail to appoint a successor depositary registered as a clearing agency under the Exchange Act within 90 days of such event;

●

we execute and deliver to the trustee an officer's certificate to the effect that such global securities shall be so exchangeable; or

●

an event of default with respect to the debt securities represented by such global securities shall have occurred and be continuing.

As long as the depositary, or its nominee, is the registered owner of a global security, the depositary or nominee will be considered the sole owner and holder of the debt securities represented by the global security for all purposes under the indenture. Except in the above limited circumstances, owners of beneficial interests in a global security:

●

will not be entitled to have the debt securities registered in their names;

●

will not be entitled to physical delivery of certificated debt securities; and

●

will not be considered to be holders of those debt securities under the indenture.

Payments on a global security will be made to the depositary or its nominee as the holder of the global security. Some jurisdictions have laws that require that certain purchasers of securities take physical delivery of such securities in definitive form. These laws may impair the ability to transfer beneficial interests in a global security.

Institutions that have accounts with the depositary or its nominee are referred to as "participants." Ownership of beneficial interests in a global security will be limited to participants and to persons that may hold beneficial interests through participants. The depositary will credit, on its book-entry registration and transfer system, the respective principal amounts of debt securities represented by the global security to the accounts of its participants. Each person owning a beneficial interest in a global security must rely on the procedures of the depositary (and, if such person is not a participant, on procedures of the participant through which such person owns its interest) to exercise any rights of a holder under the indenture.

Ownership of beneficial interests in a global security will be shown on and effected through records maintained by the depositary, with respect to participants' interests, or by any participant, with respect to interests of persons held by participants on their behalf. Payments, transfers and exchanges relating to beneficial interests in a global security will be subject to policies and procedures of the depositary. The depositary policies and procedures may change from time to time. Neither we nor the trustee will have any responsibility or liability for the depositary's acts or omissions or any participant's records with respect to beneficial interests in a global security.

Payment and Paying Agent

The provisions of this subsection will apply to the debt securities unless otherwise indicated in the prospectus supplement. Payment of interest on a debt security on any interest payment date will be made to the person in whose name the debt security is registered at the close of business on the regular record date. Payment on debt securities of a particular series will be payable at the office of a paying agent or paying agents designated by us. However, at our option, we may pay interest by mailing a check to the record holder.

We may also name any other paying agents in the prospectus supplement. We may designate additional paying agents, change paying agents or change the office of any paying agent. However, we will be required to maintain a paying agent in each place of payment for the debt securities of a particular series.

Subject to any applicable abandoned property law, all moneys paid by us to a paying agent for payment on any debt security that remain unclaimed at the end of two years after such payment was due will be repaid to us. Thereafter, the holder may look only to us for such payment.

Consolidation, Merger and Sale of Assets

Except as otherwise set forth in the applicable prospectus supplement, we may not merge or consolidate with or into any other person, in a transaction in which we are not the surviving corporation, or sell, convey, transfer, lease or otherwise dispose of all or substantially all of the properties and assets of us and our subsidiaries, taken as a whole, to any person, unless:

●

the successor or transferee is a corporation, limited liability company, partnership, trust or other entity organized and existing under the laws of Canada or any province or territory thereof, or the United States or any state thereof or the Disctrict of Columbia;

●

the successor or transferee assumes our obligations on the debt securities and under the indenture pursuant to a supplemental indenture in form reasonably satisfactory to the trustee;

●

immediately after giving effect to the transaction and treating our obligations in connection with or as a result of such transaction as having been incurred as of the time of such transaction, no default or event of default under the indenture shall have occurred and be continuing; and

●

an officer's certificate and an opinion of counsel have been delivered to the trustee in connection with the foregoing.

In the event of the above transaction, if there is a successor or transferee, then the successor or transferee will expressly assume all of our obligations under the indenture and automatically be substituted for us in the indenture and as issuer of the debt securities and may exercise every right and power of ours under the indenture with the same effect as if such successor or transferee had been named in our place in the indenture; provided, however, that the predecessor company will not be relieved of the obligation to pay principal and interest on the debt securities except in the case of a sale of all of the assets of us and our subsidiaries.

Events of Default

Event of default means, with respect to any series of debt securities, any of the following:

●

default in the payment of any interest on any debt security of that series when it becomes due and payable, and continuance of that default for a period of 30 days;

●

default in the payment of principal of, or premium on, any debt security of that series when due and payable;

●

failure on our part to comply with the covenant described under "-Consolidation, Merger and Sale of Assets";

●

default in the performance or breach of any other covenant or warranty by us in the indenture or any supplemental indenture with respect to such series (other than a covenant or warranty that has been included in the indenture or supplemental indenture solely for the benefit of a series of debt securities other than that series), which default continues uncured for a period of 90 days after (1) we receive written notice from the trustee or (2) we and the trustee receive written notice from the holders of not less than 25% in aggregate principal amount of the outstanding debt securities of that series as provided in the indenture;

●

certain events of bankruptcy, insolvency or reorganization of the Company or our significant subsidiaries; and

●

any other event of default provided with respect to debt securities of that series that is described in the applicable prospectus supplement.

We will promptly deliver to the trustee written notice of any event which with the giving of notice and the lapse of time would become a covenant event of default, or any other event of default provided with respect to debt securities of that series that is described in the applicable prospectus supplement, along with a description of the status and what action we are taking or propose to take with respect to such event of default.

No event of default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an event of default with respect to any other series of debt securities. The occurrence of an event of default may constitute an event of default under our bank credit agreements in existence from time to time. In addition, the occurrence of certain events of default or an acceleration under the indenture may constitute an event of default under certain of our other indebtedness outstanding from time to time.

If an event of default (other than an event of default resulting from certain events of bankruptcy, insolvency or reorganization of the Company) with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% in aggregate principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) of, and accrued and unpaid interest, if any, on, all debt securities of that series. In the case of an event of default resulting from certain events of bankruptcy, insolvency or reorganization of the Company, the principal (or such specified amount) of, and accrued and unpaid interest, if any, on, all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, the holders of a majority in aggregate principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if the rescission and annulment would not conflict with any judgment or decree already rendered and if all events of default with respect to that series, other than the non-payment of principal and interest, if any, with respect to debt securities of that series that has become due and payable solely because of the acceleration, have been cured or waived and all sums paid or advanced by the trustee and the reasonable compensation, expenses and disbursements of the trustee and its agents and counsel have been paid as provided in the indenture.

The indenture will provide that the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request of any holder of outstanding debt securities, unless the trustee receives security or indemnity satisfactory to the trustee against any loss, liability or expense. Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series.

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

●

that holder has previously given to the trustee written notice of a continuing event of default with respect to debt securities of that series; and

●

the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, and offered security or indemnity satisfactory to the trustee, to institute the proceeding as trustee, and the trustee has not received from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series a direction inconsistent with that request and has failed to institute the proceeding within 60 days.

Notwithstanding the foregoing, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, and premium and any interest on, that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of such payment.

The indenture will require us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. The indenture will provide that the trustee may withhold notice to the holders of debt securities of any series of any default or event of default (except in payment on any debt securities of that series) with respect to debt securities of that series if it in good faith determines that withholding notice is in the interest of the holders of those debt securities.

Modification and Waiver

We may amend or modify the indenture without the consent of any holder of debt securities of the series affected by the modifications or amendments in order to:

●

cure any ambiguity, defect or inconsistency;

●

conform the text of the indenture, including any supplemental indenture, or the debt securities to any corresponding provision of this "Description of Debt Securities" or description of the debt securities found in the prospectus supplement as evidenced by an officer's certificate;

●

provide for the issuance of additional debt securities;

●

provide for the assumption of our obligations in the case of a merger or consolidation and our discharge upon such assumption, provided that the provision under "-Consolidation, Merger and Sale of Assets"of the indenture is complied with;

●

add covenants or make any change that would provide any additional rights or benefits to the holders of the debt securities;

●

add guarantees with respect to the debt securities;

●

provide for uncertificated debt securities in addition to or in place of certificated debt securities;

●

secure the debt securities;

●

add or appoint a successor or separate trustee;

●

make any change that does not adversely affect the rights of any holder of debt securities in any material respect, as evidenced by an officer's certificate; or

●

obtain or maintain the qualification of the indenture under the Trust Indenture Act of 1939.

Other amendments and modifications of the indenture or the debt securities issued may be made with the consent of the holders of at least a majority of the aggregate principal amount of the outstanding debt securities of the affected series, and our compliance with any provision of the indenture with respect to the debt securities may be waived by written notice to the trustee by the holders of a majority of the aggregate principal amount of the outstanding debt securities of the affected series. However, no modification or amendment may, without the consent of the holder of each outstanding debt security of the affected series:

●

reduce the principal amount, any premium or change the stated maturity of any debt security or alter or waive any of the provisions with respect to the redemption or repurchase of the debt securities;

●

change the place of payment or currency in which principal, any premium or interest is paid;

●

impair the right to institute suit for the enforcement of any payment on the debt securities;

●

waive a payment default with respect to the debt securities;

●

reduce the interest rate or extend the time for payment of interest on the debt securities;

●

make any change to the amendment and modification provisions in the indenture; or

●

reduce the percentage in principal amount outstanding of debt securities the consent of the holders of which is required for any of the foregoing modifications or otherwise necessary to modify, supplement or amend the indenture or to waive any past default.

Except for certain specified provisions, the holders of at least a majority in aggregate principal amount of the outstanding debt securities of an affected series may, on behalf of the holders of all debt securities of such series, waive our compliance with provisions of the indenture. Prior to the acceleration of the maturity of the debt securities of any series pursuant to the terms of the indenture, the holders of a majority in aggregate principal amount of the outstanding debt securities of such series may, on behalf of the holders of all the debt securities of such series, waive any past default under the indenture with respect to such debt securities and its consequences, except (i) a default with respect to such series in the payment of the principal of, or premium or any interest on, the debt securities of such series or (ii) a default or event of default in respect of a covenant or provision that cannot be modified or amended without the consent of all of the holders of the outstanding debt securities of the affected series.

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance

The indenture will provide that, in certain circumstances, we may be discharged from any and all obligations in respect of the debt securities of any series (except for certain obligations to register the transfer or exchange of debt securities, to replace stolen, lost or mutilated debt securities, and to maintain paying agencies and certain provisions relating to the treatment of funds held by paying agents). We will be so discharged upon the deposit with the trustee, in trust, of money and/or U.S. government obligations in such amounts as will be sufficient, without consideration of any reinvestment of interest, in the written opinion of a nationally recognized firm of independent public accountants, a nationally recognized investment bank or a nationally recognized appraisal firm to pay and discharge each installment of principal, premium and interest in accordance with the terms of the indenture and the debt securities of that series.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service a ruling or, since the date of execution of the indenture, there has been a change in the applicable U.S. federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the beneficial owners of the debt securities of the applicable series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to U.S. federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred;

Defeasance of Certain Covenants

The indenture will provide that, upon compliance with certain conditions, we may be released from our obligation to comply with certain covenants set forth in the indenture and any supplemental indenture, and any failure to comply with those covenants will not constitute a default or an event of default with respect to the debt securities of the applicable series, or covenant defeasance. If we exercise our covenant defeasance option with respect to a series of debt securities, payment of such debt securities may not be accelerated because of an event of default related to certain events of bankruptcy, insolvency or reorganization of our significant subsidiaries.

The conditions include:

●

depositing with the trustee money and/or U.S. government obligations in such amounts as will be sufficient, without consideration of any reinvestment of interest, in the written opinion of a nationally recognized firm of independent public accountants, a nationally recognized investment bank or a nationally recognized appraisal firm to pay and discharge each installment of principal of, premium and interest in accordance with the terms of the indenture and the debt securities of the applicable series; and

●

delivering to the trustee an opinion of counsel to the effect that the beneficial owners of the debt securities of the applicable series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of the deposit and related covenant defeasance and will be subject to U.S. federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit and related covenant defeasance had not occurred.

Governing Law

The indenture and the debt securities will be governed by, and construed in accordance with, the internal laws of the State of New York.

Description of Units

As specified in the applicable prospectus supplement, we may issue units consisting of one or more of the following: Common Shares, Warrants, debt securities or any combination of such securities. The applicable prospectus supplement will describe:

●

the terms of the units and of any of our Common Shares, Warrants or debt securities comprising the units, including whether and under what circumstances the securities comprising the units may be traded separately;

●

a description of the terms of any unit agreement governing the units;

●

a description of the provisions for the payment, settlement, transfer or exchange of the units; and

●

if applicable, a discussion of any material federal income tax considerations.

Plan of Distribution

The securities may be offered through agents, through underwriters or dealers, directly to one or more purchasers or through a combination of any of these methods of sale. The specific plan of distribution, including any underwriters, dealers, agents or direct purchasers and their compensation will be identified in the applicable prospectus supplement.

Legal Matters

The validity of the securities in respect of which this prospectus is being delivered will be passed upon for us by Blake, Cassels & Graydon LLP, Vancouver, British Columbia, Canada, relating to matters of British Columbia or Canadian law, and Jones Day, relating to matters of New York or U.S. federal law. Additional legal matters may be passed upon for us or any underwriters, dealers or agents by counsel that we will name in the applicable prospectus supplement.

Experts

The consolidated financial statements of NioCorp Developments Ltd. as of June 30, 2025 and 2024, and for each of the two years in the period ended June 30, 2025, incorporated by reference in this prospectus, have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report. Such financial statements are incorporated by reference in reliance upon the report of such firm given their authority as experts in accounting and auditing.

The technical report summary for the Elk Creek Project prepared in accordance with subpart 1300 of Regulation S-K (the "S-K 1300 Elk Creek Technical Report Summary"), which is incorporated by reference in this prospectus, and the information summarized or quoted from the S-K 1300 Elk Creek Technical Report Summary included or incorporated by reference in this prospectus have been so included or incorporated by reference with the consent of the following qualified persons, as such term is defined in Item 1300 of Regulation S-K, who are responsible for the S-K 1300 Elk Creek Technical Report Summary and reviewed and approved such information summarized or quoted therefrom included or incorporated by reference in this prospectus: Dahrouge Geological Consulting USA Ltd.; Understood Mineral Resources Ltd.; Optimize Group; Tetra Tech; Adrian Brown Consultants Inc.; Metallurgy Concept Solutions; Magemi Mining Inc.; L3 Process Development; Olsson; A2GC; Scott Honan, M.Sc, SME-RM, NioCorp; Dumas Contracting Lttd.; Mahmood Khwaja, P.E., CDM Smith; and Wynand Marx, M.Eng, BBE Consulting. A matrix of the sections of the S-K 1300 Elk Creek Technical Report Summary for which each qualified person is responsible is included in the S-K 1300 Elk Creek Technical Report Summary, except that Dumas Contracting Ltd., as evidenced by its consent filed as Exhibit 23.15 to the registration statement of which this prospectus is a part, has reviewed, approved and taken responsibility for Sections 13.7.1, 13.7.2, 13.7.3, 13.7.4, 13.7.9, 13.7.10, 13.7.11, 13.7.12, 13.7.13, 13.7.14, 15.1.3, 15.1.4 and 23.1.8 of the S-K 1300 Elk Creek Technical Report Summary. Except for Scott Honan, none of the qualified persons is affiliated with NioCorp. Mr. Honan is the Chief Operating Officer of NioCorp.

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.

Other Expenses of Issuance and Distribution.

The following table sets forth the fees and expenses payable by us in connection with the sale and distribution of the securities being registered hereby. All amounts are estimates.

	Amount to be paid
SEC registration fee	$	*
Legal fees and expenses	**
Accounting fees and expenses	**
Printing expenses	**
Total	$	**

* Deferred in accordance with Rules 456(b) and 457(r) under the Securities Act of 1933 (the "Securities Act").

** These fees and expenses are calculated based on the securities offered and the number of issuances and, accordingly, cannot be estimated at this time.

Item 15.

Indemnification of Directors and Officers.

The corporate laws of British Columbia allow NioCorp Developments Ltd. ("we," "us," "our," "NioCorp" or the "Company"), and its corporate articles require it (subject to the provisions of the British Columbia Business Corporations Act (the "BCBCA") noted below and the undertakings provided in Item 17 below), to indemnify its directors, former directors, alternate directors and their heirs and legal personal representatives against all eligible penalties to which such person is or may be liable, and NioCorp must, after the final disposition of an eligible proceeding, pay the expenses actually and reasonably incurred by such person in respect of that proceeding. Each director and alternate director is deemed to have contracted with NioCorp on the terms of the indemnity contained in NioCorp's articles.

For the purposes of such an indemnification:

●

"associated corporation" means a corporation or entity referred to in paragraph (2) or (3) of the definition of "eligible party";

●

"eligible party," in relation to NioCorp, means an individual who:

(1)

is or was a director or officer of NioCorp;

(2)

is or was a director or officer of another corporation:

(i)

at a time when the corporation is or was an affiliate of NioCorp; or

(ii)

at the request of NioCorp; or

(3)

at the request of NioCorp, is or was, or holds or held a position equivalent to that of, a director or officer of a partnership, trust, joint venture or other unincorporated entity; and includes, except in the definition of "eligible proceeding" and certain other cases, the heirs and personal or other legal representatives of that individual.

●

"eligible penalty," means a judgment, penalty or fine awarded or imposed in, or an amount paid in settlement of, an eligible proceeding;

●

"eligible proceeding" means a proceeding in which an eligible party or any of the heirs and personal or other legal representatives of the eligible party, by reason of the eligible party being or having been a director or officer of, or holding or having held a position equivalent to that of a director or officer of, NioCorp or an associated corporation:

(1)

is or may be joined as a party; or

(2)

is or may be liable for or in respect of a judgment, penalty or fine in, or expenses related to, the proceeding;

●

"expenses" includes costs, charges and expenses, including legal and other fees, but does not include judgments, penalties, fines or amounts paid in settlement of a proceeding; and

●

"proceeding" includes any legal proceeding including a civil, criminal, quasi-criminal, administrative or regulatory action or proceeding; or investigative action, whether current, threatened, pending or completed.

In addition, under the BCBCA, NioCorp may pay, as they are incurred in advance of the final disposition of an eligible proceeding, the expenses actually and reasonably incurred by an eligible party in respect of that proceeding, provided that NioCorp first receives from the eligible party a written undertaking that, if it is ultimately determined that the payment of expenses is prohibited by the restrictions noted below, the eligible party will repay the amounts advanced.

Notwithstanding the provisions of NioCorp's articles noted above, NioCorp must not indemnify an eligible party or pay the expenses of an eligible party, if any of the following circumstances apply:

●

if the indemnity or payment is made under an earlier agreement to indemnify or pay expenses and, at the time that the agreement to indemnify or pay expenses was made, NioCorp was prohibited from giving the indemnity or paying the expenses by its memorandum or articles;

●

if the indemnity or payment is made otherwise than under an earlier agreement to indemnify or pay expenses and, at the time that the indemnity or payment is made, NioCorp is prohibited from giving the indemnity or paying the expenses by its memorandum or articles;

●

if, in relation to the subject matter of the eligible proceeding, the eligible party did not act honestly and in good faith with a view to the best interests of NioCorp or the associated corporation, as the case may be; or

●

in the case of an eligible proceeding other than a civil proceeding, if the eligible party did not have reasonable grounds for believing that the eligible party's conduct in respect of which the proceeding was brought was lawful.

In addition, if an eligible proceeding is brought against an eligible party by or on behalf of NioCorp or by or on behalf of an associated corporation, NioCorp must not do either of the following:

●

indemnify the eligible party under Section 160(a) of the BCBCA in respect of the proceeding; or

●

pay the expenses of the eligible party in respect of the proceeding.

Notwithstanding any of the foregoing, and whether or not payment of expenses or indemnification has been sought, authorized or declined under the BCBCA or the articles of NioCorp, on the application of NioCorp or an eligible party, the Supreme Court of British Columbia may do one or more of the following:

●

order NioCorp to indemnify an eligible party against any liability incurred by the eligible party in respect of an eligible proceeding;

●

order NioCorp to pay some or all of the expenses incurred by an eligible party in respect of an eligible proceeding;

●

order the enforcement of, or any payment under, an agreement of indemnification entered into by NioCorp;

●

order NioCorp to pay some or all of the expenses actually and reasonably incurred by any person in obtaining an order under Section 164 of the BCBCA; or

●

make any other order the court considers appropriate.

Furthermore, we have entered into an indemnification agreement with each of our directors and executive officers. The indemnification agreements provide that NioCorp will, to the fullest extent possible under applicable law, subject to other specified limitations, indemnify and hold harmless the directors and executive officers against any and all costs and expenses reasonably

incurred for, or in connection with, any civil, criminal, administrative, investigative or other proceeding, whether threatened, pending, continuing or completed, including but not limited to any act, matter, deed or thing whatsoever made, done, committed, permitted or acquiesced in.

Item 16.

Exhibits.

INDEX TO EXHIBITS

Exhibit No.	Title
1.1*	Form of Underwriting Agreement
4.1(1)	Notice of Articles of NioCorp Developments Ltd., dated April 5, 2016
4.2(1)	Articles of NioCorp Developments Ltd., as amended, effective as of January 27, 2015
4.3(2)	Amendment to Articles, effective March 17, 2023
4.4	Form of Debt Securities Indenture
4.5*	Form of Debt Securities
4.6*	Form of Warrant Agreement
4.7*	Form of Warrant Indenture
4.8*	Form of Warrant Certificate
4.9*	Form of Unit Agreement
5.1	Opinion of Blake, Cassels & Graydon LLP
5.2	Opinion of Jones Day
23.1	Consent of Blake, Cassels & Graydon LLP (included in Exhibit 5.1)
23.2	Consent of Jones Day (included in Exhibit 5.2)
23.3	Consent of Deloitte & Touche LLP
23.4	Consent of Dahrouge Geological Consulting USA Ltd.
23.5	Consent of Understood Mineral Resources Ltd.
23.6	Consent of Optimize Group Inc.
23.7	Consent of Tetra Tech
23.8	Consent of Adrian Brown Consultants Inc.
23.9	Consent of Magemi Mining Inc.
23.10	Consent of L3 Process Development
23.11	Consent of Olsson
23.12	Consent of A2GC
23.13	Consent of Metallurgy Concept Solutions
23.14	Consent of Scott Honan, M.Sc., SME-RM, NioCorp
23.15	Consent of Dumas Contracting Ltd.
23.16	Consent of Mahmood Khwaja, P.E., CDM Smith
23.17	Consent of Wynand Marx, M.Eng., BBE Consulting
24.1	Power of Attorney, contained on signature page hereto
25.1**	Form T-1 Statement of Eligibility under Trust Indenture Act of 1939 of Trustee under Debt Securities Indenture
96.1(2)	S-K 1300 Elk Creek Technical Report Summary
107	Filing Fee Table

(1)

Previously filed as an exhibit to the Company's Draft Registration Statement on Form S-1 (Registration No. 377-01354) submitted to the Securities and Exchange Commission (the "SEC") on July 26, 2016 and incorporated herein by reference.

(2)

Previously filed as an exhibit to the Company's Current Report on Form 8-K (File No. 001-41655) filed with the SEC on March 17, 2023 and incorporated herein by reference.

(3)

Previously filed as an exhibit to the Company's Annual Report on Form 10-K (File No. 000-55710) filed with the SEC on September 6, 2022 and incorporated herein by reference.

*

To be filed by amendment or as an exhibit to a report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended and incorporated herein by reference.

**	To be filed in accordance with the requirements of Section 305(b)(2) of the Trust Indenture Act of 1939 (the "Trust Indenture Act").

Item 17. Undertakings.

The undersigned registrant hereby undertakes:

(1)

To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i)

To include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii)

To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the "Calculation of Filing Fee Tables" in the effective registration statement; and

(iii)

To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

Provided, however, that paragraphs (i), (ii) and (iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 (the "Exchange Act") that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2)

That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3)

To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4)

That, for the purpose of determining liability under the Securities Act to any purchaser:

(i)

Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii)

Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(5)

That, for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the

securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i)

Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii)

Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii)

The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv)

Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(6)

That, for purposes of determining any liability under the Securities Act, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(7)

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

(8)

The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the SEC under Section 305(b)(2) of the Trust Indenture Act.

SIGNATURES

Pursuant to the requirements of the Securities Act, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement on Form S-3 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Centennial, State of Colorado, on October 10, 2025.

	NIOCORP DEVELOPMENTS LTD.
	By:	/s/ Mark A. Smith
		Mark A. Smith
		President and Chief Executive Officer
		(Principal Executive Officer)

Pursuant to the requirements of the Securities Act, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

KNOW ALL PERSONS BY THESE PRESENTS, that each of the directors and officers of the registrant whose signature appears below constitutes and appoints Mark A. Smith and Neal Shah, or either of them, as true and lawful attorneys-in-fact and agents with full power of substitution and re-substitution, for him or her and in his or her name, place and stead, in any and all capacities to sign this registration statement and any or all amendments to said registration statement (including post-effective amendments and registration statements filed pursuant to Rule 462 and otherwise), and to file the same, with all exhibits thereto, and other documents in connection therewith, the SEC granting unto said attorneys-in-fact and agents the full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the foregoing, as to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or his or her substitute, may lawfully do or cause to be done by virtue hereof.

/s/ Mark A. Smith	President, Chief Executive Officer (Principal Executive Officer and Authorized U.S. Representative) and Chairman of the Board of Directors	October 10, 2025
Mark A. Smith
/s/ Neal Shah	Chief Financial Officer (Principal Financial and Accounting Officer)	October 10, 2025
Neal Shah
/s/ Anthony W. Fulton	Director	October 10, 2025
Anthony W. Fulton
/s/ David C. Beling	Director	October 10, 2025
David C. Beling
/s/ Nilsa Guerrero-Mahon	Director	October 10, 2025
Nilsa Guerrero-Mahon
/s/ Peter Oliver	Director	October 10, 2025
Peter Oliver
/s/ Dean C. Kehler	Director	October 10, 2025
Dean C. Kehler
/s/ Michael G. Maselli	Director	October 10, 2025
Michael G. Maselli