Supplemental Prospectus (Form 424B5)

Filed Pursuant to Rule 424(b)(5)
Registration Statement No. 333-296756

Prospectus Supplement

(To Prospectus dated June 16, 2026)

Magnachip Semiconductor Corporation

Up to $50,000,000

Common Stock

We have entered into an At Market Issuance Sales Agreement (the "sales agreement") with B. Riley Securities, Inc., as our sales agent (the "sales agent"), relating to the sale of shares of our common stock, par value $0.01 per share ("common stock"), offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock from time to time through or to the sales agent, acting as our agent or principal, having an aggregate offering price of up to $50,000,000.

Sales of shares of our common stock under this prospectus supplement and the accompanying prospectus, if any, may be made by any method deemed to be an "at the market offering" as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the "Securities Act"). The sales agent is not required to sell any specific number or dollar amount of shares of our common stock. The sales agent has agreed to use its commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us, consistent with its normal trading and sales practices, on mutually agreed terms between the sales agent and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The sales agent will be entitled to compensation under the terms of the sales agreement at a commission rate up to 3.0% of the gross sales price per share sold. In connection with the sale of common stock on our behalf, the sales agent will be deemed to be an "underwriter" within the meaning of the Securities Act, and the compensation of the sales agent will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the sales agent with respect to certain liabilities, including liabilities under the Securities Act. See "Plan of Distribution" for additional information regarding compensation to be paid to the sales agent.

Our common stock is traded on New York Stock Exchange under the symbol "MX". On June 16, 2026, the last reported sale price of our common stock was $5.50 per share.

Investing in our common stock involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading "Risk Factors" beginning on page S-5 of this prospectus supplement, the accompanying prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus supplement.

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

B. Riley Securities

The date of this prospectus supplement is June 17, 2026.

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

Neither we nor the sales agent (or any of its affiliates) have authorized anyone to provide you with information different from that contained or incorporated by reference in this prospectus supplement, the accompanying prospectus or any free writing prospectus prepared by us or on our behalf. Neither we nor the sales agent (or any of its affiliates) take any responsibility for, or can provide any assurance as to the reliability of, any information other than the information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus or any free writing prospectus prepared by us or on our behalf. We and the sales agent are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted.

You should assume that the information appearing or incorporated by reference in this prospectus supplement, the accompanying prospectus or any free writing prospectus prepared by us or on our behalf is accurate only as of their respective dates or on the date or dates which are specified in such documents, and that any information in documents that we have incorporated by reference is accurate only as of the date of such document incorporated by reference. Our business, financial condition, liquidity, results of operations and prospects may have changed since those dates.

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ABOUT THIS PROSPECTUS SUPPLEMENT

Unless the context requires otherwise, references in this prospectus supplement to the "Company," "Magnachip," "we," "us" and "our" refer to Magnachip Semiconductor Corporation and its consolidated subsidiaries.

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of our common stock and certain other matters relating to us and our business. The second part, the accompanying prospectus, contains and incorporates by reference important business and financial information about us, a description of our common stock and certain other information about us and this offering. This prospectus supplement, the accompanying prospectus and any related free writing prospectus are part of a registration statement that we filed with the SEC using a "shelf" registration process.

The information contained in this prospectus supplement may add, update or change information contained in the accompanying prospectus or in documents that we file or have filed with the SEC. You should read both this prospectus supplement and the accompanying prospectus, together with additional information described below under the headings "Where You Can Find More Information" and "Incorporation of Certain Documents by Reference" and any free writing prospectus that we have authorized for use in connection with this offering. To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or documents incorporated by reference filed before the date of this prospectus supplement, the information in this prospectus supplement will supersede such information. Any statement modified or superseded by a statement made in a subsequently filed document that is incorporated or deemed to be incorporated by reference in this prospectus supplement will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. For further information, we refer you to our Registration Statement, including its exhibits, of which this prospectus supplement and the accompanying prospectus form a part. We are subject to the informational requirements of the Exchange Act, and therefore file reports and other information with the SEC. Statements contained in this prospectus supplement, the accompanying prospectus and any related free writing prospectus about the provisions or contents of any agreement or other document are only summaries. If SEC rules require that any agreement or document be filed as an exhibit to the Registration Statement, you should refer to that agreement or document for its complete contents.

Neither we nor the sales agent have authorized anyone to provide you with any information other than that contained or incorporated by reference in this prospectus supplement and the accompanying prospectus, along with the information contained in any free writing prospectuses we have authorized for use in connection with this offering. Neither we nor the sales agent take any responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. This prospectus supplement and the accompanying prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so.

The information appearing in this prospectus supplement, the accompanying prospectus and any related free writing prospectus is accurate only as of the date on the front of the document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus supplement, the accompanying prospectus and any related free writing prospectus, or any sale of securities. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus supplement, the accompanying prospectus, any related free writing prospectus and the information incorporated herein or therein by reference contains market data, industry statistics and other data that have been obtained or compiled from information made available by independent third parties. We have not independently verified the accuracy and completeness of such data.

We use various trademarks and trade names in our business, including without limitation our corporate name and logo. All other trademarks or trade names referred to in this prospectus are the property of their respective

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owners. Solely for convenience, the trademarks and trade names in this prospectus may be referred to without the ^® and ^™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto.

FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein contains forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Forward-looking statements give our current expectations and projections relating to our financial condition, results of operations, plans, objectives, future performance and business. You can identify these statements by the fact that they do not relate strictly to historical or current facts. These statements may include words such as "anticipate," "estimate," "expect," "project," "intend," "plan," "believe" and other words and terms of similar meaning in connection with any discussion of the timing or nature of future operating or financial performance or other events. All statements other than statements of historical facts included in this prospectus supplement, the accompanying prospectus and any related free writing prospectus that address activities, events or developments that we expect, believe or anticipate will or may occur in the future are forward-looking statements.

These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements, including, but not limited to, those described under "Risk Factors" in this prospectus supplement, the applicable prospectus and any related free writing prospectus, and in any other documents incorporated herein or therein (including in our most recent annual report on Form 10-K, subsequent quarterly reports on Form 10-Q and other filings we make with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act). Some of these risks and uncertainties may in the future be amplified by a global crises and/or any response to such a crisis and there may be additional risks that we consider immaterial or which are unknown. It is not possible to predict or identify all such risks. It is not possible to predict or identify all such risks.

These forward-looking statements are largely based on our expectations and beliefs concerning future events, which reflect estimates and assumptions made by our management. These estimates and assumptions reflect our best judgment based on currently known market conditions and other factors relating to our operations and business environment, all of which are difficult to predict and many of which are beyond our control. Although we believe our estimates and assumptions to be reasonable, they are inherently uncertain and involve a number of risks and uncertainties that are beyond our control. In addition, management's assumptions about future events may prove to be inaccurate. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. Management cautions all readers that the forward-looking statements contained in this prospectus supplement, the accompanying prospectus or any related free writing prospectus, are not guarantees of future performance, and we cannot assure any reader that those statements will be realized or the forward-looking events and circumstances will occur.

All forward-looking statements and reasons why results may differ included in this prospectus supplement or incorporated by reference herein are made as of the date hereof and we do not intend to update any forward-looking statements except as required by law or applicable regulations.

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RISK FACTORS

Investing in our securities involves a high degree of risk. Before you invest in shares of our common stock, you should carefully consider the risks and uncertainties described under "Risk Factors" in our most recent annual report on Form 10-K as supplemented or updated in our most recent quarterly report on Form 10-Q, any current report on Form 8-K, as well as the accompanying prospectus and any related free writing prospectus, together with all of the other information included or incorporated by reference in this prospectus supplement and in any accompanying prospectus or related free writing prospectus, as updated by our annual or quarterly reports for subsequent fiscal years or fiscal quarters that we file with the SEC and that are so incorporated. Each of the risks described in these documents could materially and adversely affect our business, financial condition, liquidity, results of operations and prospects, and could result in a partial or complete loss of your investment.

In connection with the forward-looking statements that appear in this prospectus supplement and the accompanying prospectus, you should also carefully review the cautionary statement referred to under "Forward-Looking Statements" in this prospectus supplement.

Risks Related to This Offering

We will have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

We currently intend to use the net proceeds of this offering for general corporate purposes, which may include investments in strategic growth initiatives and technologies that support AI data centers and robotics, as further described in the section of this prospectus supplement titled "Use of Proceeds." We will have broad discretion in the application of the net proceeds and investors will be relying on the judgment of our management regarding the application of the proceeds of this offering. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. Our management might not apply the net proceeds from this offering in ways that ultimately increase the value of your investment. The failure by our management to apply these funds effectively could harm our business. Pending the use of the net proceeds from this offering, we may invest such net proceeds in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline

If you purchase shares of common stock in this offering, you may experience future dilution as a result of future equity offerings.

In order to raise additional capital, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in any other offering at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to those of existing stockholders. The price per share at which we sell additional shares of our common stock, or securities convertible or exchangeable into common stock, in future transactions may be higher or lower than the price per share paid by investors in this offering.

We do not intend to pay dividends on our common stock, so any returns will be limited to the value of our common stock.

We currently anticipate that we will retain any future earnings to finance the continued development, operation and expansion of our business. As a result, we do not anticipate declaring or paying any cash dividends or other distributions in the foreseeable future. Further, if we were to enter into a credit facility or issue debt securities or preferred stock in the future, we may become contractually restricted from paying dividends. If we do not pay

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dividends, our common stock may be less valuable because stockholders must rely on sales of their common stock after price appreciation, which may never occur, to realize any gains on their investment.

The actual number of shares of common stock we will issue under the sales agreement, at any one time or in total, is uncertain.

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to the sales agent at any time throughout the term of the sales agreement. The per share price of the shares of common stock that are sold by the sales agent after delivering a placement notice will fluctuate based on the market price of our common stock during the sales period and limits we set with the sales agent. Because the price per share of each share of common stock sold will fluctuate based on the market price of our common stock during the sales period, it is not possible at this stage to predict the number of shares of common stock that will be ultimately issued or the gross proceeds to be raised in connection with those sales.

The common stock offered hereby will be sold in "at the market offerings," and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares sold, and there is no minimum or maximum sales price. Investors may experience a decline in the value of their shares as a result of share sales made at prices lower than the prices they paid.

The sale of our common stock in this offering and any future sales of our common stock may depress our stock price and our ability to raise funds in new stock offerings.

Sales of our common stock in this offering and the public market following this offering could lower the market price of our common stock. Sales may also make it more difficult for us to sell equity securities or equity-related securities in the future at a time and price that our management deems acceptable, or at all.

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USE OF PROCEEDS

We may issue and sell shares of our common stock having aggregate gross sales proceeds of up to $50 million from time to time pursuant to the sales agreement. The amount of proceeds from this offering will depend upon the number of shares of our common stock sold and the market price at which they are sold. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. There can be no assurance that we will sell any shares under or fully utilize the sales agreement as a source of financing.

We currently intend to use the net proceeds from this offering, if any, after deducting commissions and offering expenses payable by us, for general corporate purposes, which may include investments in strategic growth initiatives and technologies that support AI data centers and robotics. We may also use net proceeds to fund potential acquisitions of, or investments in, complementary businesses, products, services and technologies. We have not entered into any agreements or commitments with respect to any material acquisitions or investments at this time.

The expected use of the net proceeds from this offering represents our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve. The amounts and timing of our actual expenditures will depend on numerous factors, including the factors described under "Risk Factors" in this prospectus supplement, the accompanying prospectus, and in the documents incorporated by reference herein, as well as the amount of cash used in our operations. We may find it necessary or advisable to use the net proceeds for other purposes, and we will have broad discretion in the application of the net proceeds.

Pending use of net proceeds as described above, we may temporarily invest the net proceeds in a variety of capital preservation instruments, including high quality, investment grade instruments, certificates of deposit or direct or guaranteed obligations of the U.S. government, or may hold such proceeds as cash, until they are used for their stated purpose. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

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DIVIDEND POLICY

We have never declared or paid any cash dividends on our capital stock. We do not anticipate paying any dividends on our capital stock in the foreseeable future. We currently intend to retain all available funds and any future earnings to fund the development and growth of our business. Any future determination to declare dividends will be subject to the discretion of our board of directors and will depend on various factors, including applicable laws, our results of operations, financial condition, future prospects and any other factors deemed relevant by our board of directors. Further, our ability to declare dividends may be limited by our holding company structure and the terms of financing or other agreements entered into by us or our subsidiaries from time to time. Investors should not purchase our common stock with the expectation of receiving cash dividends.

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PLAN OF DISTRIBUTION

We have entered into the sales agreement with the sales agent, under which we may offer and sell our shares of common stock from time to time through or to the sales agent acting as agent or principal. Pursuant to this prospectus supplement, we may offer and sell up to $50,000,000 of our shares of common stock. Sales of our shares of common stock, if any, under this prospectus supplement and the accompanying prospectus will be made by any method that is deemed to be an "at the market offering" as defined in Rule 415(a)(4) under the Securities Act.

Each time we wish to issue and sell shares of common stock under the sales agreement, we will notify the sales agent of the number or dollar value of shares to be issued, the dates on which such sales are anticipated to be made, any limitation on the number of shares to be sold in any one day and any minimum price below which sales may not be made. Once we have so instructed the sales agent, unless the sales agent declines to accept the terms of such notice, the sales agent has agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on such terms. The obligations of the sales agent under the sales agreement to sell our shares of common stock are subject to a number of conditions that we must meet.

The settlement of sales of shares between us and the sales agent is generally anticipated to occur on the first trading day following the date on which the sale was made. Sales of our shares of common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and the sales agent may agree upon. There is no arrangement for funds to be received in an escrow, trust, or similar arrangement.

We will pay the sales agent a commission up to 3.0% of the aggregate gross proceeds we receive from each sale of our shares of common stock. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. In addition, we have agreed to reimburse the sales agent for the fees and disbursements of its counsel in connection with (a) entering into the transactions contemplated by the sales agreement in an amount not to exceed $100,000 in the aggregate, payable upon the execution of the sales agreement and (b) ongoing diligence arising from the transactions contemplated by the sales agreement in an amount not to exceed $7,500 in the aggregate per calendar quarter. We estimate that the total expenses for the offering, excluding any commissions or expense reimbursement payable to the sales agent under the terms of the sales agreement, will be approximately $700,000. The remaining sale proceeds, after deducting any other transaction fees, will equal our net proceeds from the sale of such shares.

The sales agent will provide confirmation to us before the open on the New York Stock Exchange on the day following each day on which shares of common stock are sold under the sales agreement.

In connection with the sale of the shares of common stock on our behalf, the sales agent will be deemed to be an "underwriter" within the meaning of the Securities Act, and the compensation of the sales agent will be deemed to be underwriting commissions or discounts. We have agreed to indemnify the sales agent against certain civil liabilities, including liabilities under the Securities Act. We have also agreed to contribute to payments the sales agent may be required to make in respect of such liabilities.

This offering of our shares of common stock pursuant to the sales agreement will terminate upon the earlier of (i) the sale of all shares of common stock subject to the sales agreement; or (ii) the termination of the sales agreement as permitted therein. We and the sales agent may each terminate the sales agreement at any time upon five (5) days' prior notice.

This summary of the material provisions of the sales agreement does not purport to be a complete statement of its terms and conditions. A copy of the sales agreement will be filed as an exhibit to a current report on Form 8-K filed under the Exchange Act, and will be incorporated by reference in this prospectus supplement.

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The sales agent and its affiliates may in the future provide various investment banking, commercial banking, financial advisory and other financial services for us and our affiliates, for which services they may in the future receive customary fees. In the course of its business, the sales agent may actively trade our securities for its own account or for the accounts of customers, and, accordingly, the sales agent may at any time hold long or short positions in such securities.

A prospectus supplement and the accompanying prospectus in electronic format may be made available on a website maintained by the sales agent, and the sales agent may distribute the prospectus supplement and the accompanying prospectus electronically.

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LEGAL MATTERS

The validity of the securities offered by this prospectus will be passed upon for us by Goodwin Procter LLP, Redwood City, California. Certain legal matters in connection with this offering will be passed upon for the sales agent by Duane Morris LLP, New York, New York.

EXPERTS

EY Han Young (formerly, Ernst & Young Han Young), independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025 as set forth in their report, which is incorporated by reference in this prospectus supplement and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young Han Young's report, given on their authority as experts in accounting and auditing.

Samil PricewaterhouseCoopers, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2024 as set forth in their report, which is incorporated by reference in this prospectus supplement and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Samil PricewaterhouseCoopers' report, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement is part of a shelf registration statement that we have filed with the SEC. This prospectus supplement does not contain all of the information set forth in the registration statement and its exhibits and schedules in accordance with SEC rules and regulations. For further information with respect to us and the securities being offered by this prospectus supplement, you should read the registration statement, including its exhibits and schedules. Statements contained in this prospectus supplement and the accompanying prospectus, including documents that we have incorporated by reference, as to the contents of any contract or other document referred to are not necessarily complete, and, with respect to any contract or other document filed as an exhibit to the registration statement or any other such document, each such statement is qualified in all respects by reference to the corresponding exhibit. You should review the complete contract or other document to evaluate these statements. You may obtain copies of the registration statement and its exhibits via the SEC's EDGAR database or our website.

We file annual, quarterly and current reports, proxy statements and other documents with the SEC under the U.S. Securities Exchange Act of 1934, as amended, or 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 also make these documents available on our website at www.investors.magnachip.com. Our website and the information contained or connected to our website is not incorporated by reference in this prospectus supplement, and you should not consider it part of this prospectus supplement.

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INCORPORATION BY REFERENCE

SEC rules permit us to incorporate information by reference in this 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 supplement, except for information superseded by information contained in this prospectus supplement or in any subsequently filed incorporated document. This prospectus supplement incorporates 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.

All documents that we file (but not those that we furnish) pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, after the date of the initial registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement shall be deemed to be incorporated by reference into this prospectus and will automatically update and supersede the information in this prospectus, and any previously filed documents.

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference in this prospectus or the applicable prospectus supplement shall be deemed to be modified or superseded for purposes of this prospectus and such applicable prospectus supplement to the extent that a statement contained in this prospectus or such applicable prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference in this prospectus and such applicable prospectus supplement, modifies or supersedes such earlier statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus or such applicable prospectus supplement. Nothing in this prospectus shall be deemed to incorporate information furnished but not filed with the SEC pursuant to Item 2.02 or Item 7.01 of Form 8-K.

Upon request, we will provide, without charge, to each person, including any beneficial owner, to whom a copy of this prospectus or an applicable prospectus supplement is delivered, a copy of the documents incorporated by reference into this prospectus or such prospectus supplement but not delivered with this prospectus or such prospectus supplement. You may request a copy of these filings, and any exhibits we have specifically incorporated by reference as an exhibit in this prospectus or such prospectus supplement, at no cost by writing us at the following address: c/o Magnachip Semiconductor, Ltd., 15F, 76 Jikji-daero 436beon-gil, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28581, Republic of Korea; Attention: Investor Relations; email address: [email protected] or by telephone at: +82 (2) 6903-3000.

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Filed Pursuant to Rule 424(b)(3)
Registration No. 333-296756

PROSPECTUS

Magnachip Semiconductor Corporation

$50,000,000

Common Stock

Preferred Stock

Warrants

Rights

Units

From time to time, we may offer and sell up to $50,000,000 in the aggregate of the securities identified above in one or more offerings and at prices and on terms that we will determine at the time of the offering.

This prospectus describes the general manner in which these securities may be offered using this prospectus. Each time we offer securities using this prospectus, we will specify in one or more accompanying prospectus supplements the terms of the securities offered and other details regarding the offering thereof. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus with respect to that offering. You should carefully read this prospectus and the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of our securities.

The securities covered by this prospectus may be sold directly by us to investors, through agents designated by us from time to time or through underwriters or dealers at prices and on terms to be determined at the time of offering. We will include in an applicable prospectus supplement the names of any underwriters or agents and any applicable commissions or discounts. Additional information on the methods of sale appears under "Plan of Distribution" in this prospectus. We will also describe in an applicable prospectus supplement the way(s) in which we expect to use the net proceeds we receive from any sale.

Our common stock is listed on the New York Stock Exchange under the symbol "MX." On June 16, 2026, the closing price for our common stock, as reported on the New York Stock Exchange, was $5.50 per share.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading "Risk Factors" on page 8 of this prospectus (and any applicable prospectus supplement or free writing prospectus) and under any similar heading in the documents that are incorporated by reference into this prospectus, as well as "Special Note Regarding Forward-Looking Statements" on page 5 of this prospectus. You should read the entire prospectus carefully before you make your investment decision.

We are a smaller reporting company as defined under federal securities laws and, as such, may elect to comply with certain reduced public company reporting requirements for future filings.

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

This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

The date of this prospectus is June 16, 2026.

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ABOUT THIS PROSPECTUS

This prospectus is part of a shelf registration statement that we have filed with the Securities and Exchange Commission, or the SEC, under the Securities Act of 1933, as amended, or the Securities Act.

Under the shelf registration process, we may from time to time sell the securities described in this prospectus in one or more offerings with an aggregate offering price of up to $50,000,000 as described in this prospectus. This prospectus describes the general manner in which we may offer the securities described in this prospectus. Each time we sell securities pursuant to the registration statement we will provide a prospectus supplement that will contain specific information about the offering and the securities offered, and may also add, update or change information contained in this prospectus. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. If there is any inconsistency between information in this prospectus and any accompanying prospectus supplement or free writing prospectus, you should rely on the information in the most recent applicable prospectus supplement or free writing prospectus and documents incorporated by reference herein and therein. This prospectus may not be used to offer to sell, solicit an offer to buy or consummate a sale of our securities unless it is accompanied by a prospectus supplement.

This prospectus, together with any accompanying prospectus supplement (and any applicable free writing prospectuses), contains important information you should know before investing in our securities, including important information about us and the securities being offered. You should carefully read these documents, as well as the additional information contained in the documents described under "Where You Can Find More Information" and "Incorporation of Certain Information by Reference" in both this prospectus and the applicable prospectus supplement (and any applicable free writing prospectuses), and in particular the annual, quarterly and current reports and other documents we file with the SEC. Neither this prospectus nor any accompanying prospectus supplement or free writing prospectus is an offer to sell these securities or is soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

You should rely only on the information contained or incorporated by reference in this prospectus and in any applicable prospectus supplement to this prospectus or free writing prospectus. We have not authorized any other person to provide you with different or additional information. If anyone provides you with different, additional or inconsistent information, you should not rely on it. 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 assume that the information appearing in this prospectus, any applicable prospectus supplement or any free writing prospectus we authorize to be delivered to you is accurate only as of the date of that document or any other date set forth in that document. Additionally, any information we have incorporated by reference in this prospectus or in any applicable prospectus supplement is accurate only as of the date of the document incorporated by reference or other date set forth in that document, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any sale of securities. Our business, financial condition, results of operations, cash flow and prospects may have changed since that date.

This prospectus, any applicable prospectus supplement, any applicable free writing prospectus and the information incorporated herein or therein by reference contains market data, industry statistics and other data that have been obtained or compiled from information made available by independent third parties. We have not independently verified the accuracy and completeness of such data. This prospectus, any applicable prospectus supplement, any applicable free writing prospectus and the information incorporated herein or therein by reference include trademarks, service marks and trade names owned by us or other companies. Solely for convenience, we may refer to our trademarks included or incorporated by reference in this prospectus, any applicable prospectus supplement or any free writing prospectus without the TM or ^® symbols, but any such references are not intended to indicate that we will not assert, to the fullest extent permitted under applicable law, our rights to our trademarks or other intellectual property. All trademarks, service marks and trade names included or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus are the property of their respective owners.

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When used in this prospectus, the terms "Company," "Magnachip," "we," "us" and "our" refer to Magnachip Semiconductor Corporation and its consolidated subsidiaries unless otherwise specified or the context otherwise requires.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

Forward-looking statements give our current expectations and projections relating to our financial condition, results of operations, plans, objectives, future performance and business. You can identify these statements by the fact that they do not relate strictly to historical or current facts. These statements may include words such as "anticipate," "estimate," "expect," "project," "intend," "plan," "believe" and other words and terms of similar meaning in connection with any discussion of the timing or nature of future operating or financial performance or other events. All statements other than statements of historical facts included in this prospectus and any accompanying prospectus supplement or free writing prospectus that address activities, events or developments that we expect, believe or anticipate will or may occur in the future are forward-looking statements.

These forward-looking statements are largely based on our expectations and beliefs concerning future events, which reflect estimates and assumptions made by our management. These estimates and assumptions reflect our best judgment based on currently known market conditions and other factors relating to our operations and business environment, all of which are difficult to predict and many of which are beyond our control. Although we believe our estimates and assumptions to be reasonable, they are inherently uncertain and involve a number of risks and uncertainties that are beyond our control. In addition, management's assumptions about future events may prove to be inaccurate. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. Management cautions all readers that the forward-looking statements contained in this prospectus, or any accompanying prospectus supplement, are not guarantees of future performance, and we cannot assure any reader that those statements will be realized or the forward-looking events and circumstances will occur. Our future financial condition and results of operations, as well as any forward-looking statements, are subject to inherent risks and uncertainties, including, but not limited to, those described under "Risk Factors" in this prospectus, any applicable prospectus supplement and any related free writing prospectus, and in any other documents incorporated herein or therein (including in our most recent annual report on Form 10-K, subsequent quarterly reports on Form 10-Q and other filings we make with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act).

All forward-looking statements and reasons why results may differ included in this prospectus or incorporated by reference herein are made as of the date hereof and we do not intend to update any forward-looking statements except as required by law or applicable regulations.

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RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully consider the risks and uncertainties described under "Risk Factors" in our most recent annual report on Form 10-K as supplemented or updated in our most recent quarterly report on Form 10-Q, any current report on Form 8-K, as well as any accompanying prospectus supplement or related free writing prospectus, together with all of the other information included or incorporated by reference in this prospectus and in any accompanying prospectus supplement or related free writing prospectus, as updated by our annual or quarterly reports for subsequent fiscal years or fiscal quarters that we file with the SEC and that are so incorporated. See "Where You Can Find More Information" and "Incorporation of Certain Information by Reference" for information about how to obtain a copy of these documents. You should also carefully consider the risks and other information that may be contained in, or incorporated by reference into, any prospectus supplement or free writing prospectus relating to specific offerings of securities.

If any of these risks actually occurs, our business, results of operations and financial condition could suffer. In that case, the trading price of our securities could decline, and you could lose all or part of your investment. Additional risks and uncertainties not currently known to us, or that we currently believe are immaterial, may also adversely affect our business, operating results and financial condition and the value of an investment in our securities. In addition, past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods.

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USE OF PROCEEDS

Unless otherwise described in the applicable prospectus supplement or in any free writing prospectus we have authorized for use in connection with a specific offering, we intend to use the net proceeds from the sale of any securities described in this prospectus for general corporate purposes, which may include working capital and capital expenditures, research and development expenses, general and administrative expenses and other general corporate purposes. We may also use net proceeds to fund potential acquisitions of, or investments in, complementary businesses, products, services and technologies. We have not entered into any agreements or commitments with respect to any material acquisitions or investments at this time.

We may set forth additional information concerning our expected use of net proceeds from sales of securities in the applicable prospectus supplement relating to the specific offering. Pending use of net proceeds as described above, we may temporarily invest the net proceeds in a variety of capital preservation instruments, including high quality, investment grade instruments, certificates of deposit or direct or guaranteed obligations of the U.S. government, or may hold such proceeds as cash, until they are used for their stated purpose. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

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DIVIDEND POLICY

We have never declared or paid any cash dividends on our capital stock. We do not anticipate paying any dividends on our capital stock in the foreseeable future. We currently intend to retain all available funds and any future earnings to fund the development and growth of our business. Any future determination to declare dividends will be subject to the discretion of our board of directors and will depend on various factors, including applicable laws, our results of operations, financial condition, future prospects and any other factors deemed relevant by our board of directors. Investors should not purchase our common stock with the expectation of receiving cash dividends.

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GENERAL DESCRIPTION OF SECURITIES

We may offer shares of our common stock or preferred stock, warrants or other rights to purchase common stock or preferred stock, or units consisting of combinations of the foregoing, either individually or in combination with other securities, in each case from time to time under this prospectus, together with the applicable prospectus supplement or any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of offering. This prospectus provides you with a general description of the securities we may offer. At the time we offer a type or series of securities, we will provide a prospectus supplement describing the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

This prospectus may not be used to offer or sell securities unless accompanied by a prospectus supplement. The prospectus supplement may add, update or change any of the information contained in this prospectus or in the documents incorporated by reference in this prospectus. We urge you to read the prospectus supplement related to any securities being offered.

We may sell the securities directly to investors or to or through underwriters, dealers or agents. We and our underwriters, dealers or agents reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through underwriters or agents, we will include in the applicable prospectus supplement (a) the names of the underwriters or agents and applicable fees, discounts and commissions to be paid to them, (b) details regarding over-allotment options, if any, and (c) net proceeds to us, if any.

The following descriptions are not complete and may not contain all the information you should consider before investing in any securities we may offer hereunder; they are summarized from, and qualified by reference to, our certificate of incorporation, as amended, or our Certificate of Incorporation, our amended and restated bylaws, or our Bylaws, and the other documents referred to in the descriptions, all of which are or will be publicly filed with the SEC, as applicable. See "Where You Can Find More Information."

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DESCRIPTION OF CAPITAL STOCK

The following summary description of our common stock and preferred stock, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of our common stock and preferred stock that we may offer under this prospectus. The following description of our common stock and preferred stock does not purport to be complete and is subject to, and qualified in its entirety by, our Certificate of Incorporation and our Bylaws, which are exhibits to the registration statement of which this prospectus forms a part, and by applicable law. The terms of our common stock and preferred stock may also be affected by Delaware law.

General

Our Certificate of Incorporation provides that the Company may issue 155,000,000 shares of capital stock, of which 150,000,000 shares are designated as common stock, par value $0.01 per share, and 5,000,000 shares are designated as of preferred stock, par value $0.01 per share.

Common Stock

Voting Rights

Holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. Our stockholders do not have cumulative voting rights in the election of directors. Except as required by law or our Certificate of Incorporation and Bylaws, the vote of a majority of the shares represented in person or by proxy at any meeting at which a quorum is present will be sufficient for the transaction of any business at a meeting.

Dividends

Subject to preferences held by, or that may be granted to, any outstanding shares of preferred stock, holders of our common stock will be entitled to receive ratably those dividends as may be declared by our board of directors out of funds legally available for such distributions, as well as any other distributions made to our stockholders.

Other Rights

In the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all of our assets remaining after we pay our liabilities and any liquidation preferences granted to the holders of outstanding shares of preferred stock.

Holders of our common stock have no preemptive or other subscription or conversion rights.

There are no redemption or sinking fund provisions applicable to our common stock.

Exchange Listing

Our common stock is listed on the New York Stock Exchange under the symbol "MX." On June 16, 2026, the closing price for our common stock, as reported on the New York Stock Exchange, was $5.50 per share.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Equiniti Trust Company, LLC.

Preferred Stock

Our Certificate of Incorporation authorizes the issuance of 5,000,000 shares of blank check preferred stock with such designation, rights and preferences as may be determined from time to time by our board of directors.

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Accordingly, our board of directors is empowered, without stockholder approval, to issue preferred stock with dividend, liquidation, conversion, voting or other rights which could adversely affect the voting power or other rights of the holders of common stock. The preferred stock could be utilized as a method of discouraging, delaying or preventing a change in control of us.

Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in our control that may otherwise benefit holders of our common stock and may adversely affect the market price of our common stock and the voting and other rights of the holders of our common stock.

A prospectus supplement relating to any series of preferred stock being offered will include specific terms relating to the offering. They will include, where applicable:

Certain Anti-Takeover Effects of Delaware Law

We are subject to the provisions of Section 203 of the Delaware General Corporation Law, or the DGCL, regulating corporate takeovers and which has an anti-takeover effect with respect to transactions not approved in

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advance by our board of directors, including discouraging takeover attempts that might result in a premium over the market price for shares of our common stock. In general, those provisions prohibit a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years following the date that the stockholder became an interested stockholder, unless:

In general, DGCL Section 203 defines a business combination to include the following:

In general, DGCL Section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by any such entity or person.

A Delaware corporation may opt out of this provision by express provision in its original certificate of incorporation or by amendment to its certificate of incorporation or bylaws approved by its stockholders. However, we have not opted out of this provision.

Certain Provisions of Our Certificate of Incorporation and Bylaws

Provisions in our Certificate of Incorporation and Bylaws may have the effect of delaying or preventing a change of control or changes in our management. Among other things, our Certificate of Incorporation and Bylaws:

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DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplements, summarizes the material terms and provisions of the warrants that we may offer under this prospectus and the related warrant agreements and warrant certificates. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. If we indicate in the prospectus supplement, the terms of any warrants offered under that prospectus supplement may differ from the terms described below. Specific warrant agreements will contain additional important terms and provisions and will be incorporated by reference as an exhibit to the registration statement, which includes this prospectus.

General

We may issue warrants for the purchase of common stock or preferred stock in one or more series. We may issue warrants independently or together with common stock or preferred stock, and the warrants may be attached to or separate from these securities.

We will evidence each series of warrants by warrant certificates that we will issue under a separate warrant agreement. We will enter into the warrant agreement with a warrant agent. We will indicate the name and address of the warrant agent in the applicable prospectus supplement relating to a particular series of warrants.

We will describe in the applicable prospectus supplement the terms of the series of warrants, including:

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DESCRIPTION OF RIGHTS

We may issue subscription rights, or Rights, to purchase our common stock, preferred stock, warrants, or units consisting of some or all of these securities. These Rights may be offered independently or together with any other securities offered hereby and may or may not be transferable by the stockholder receiving the Rights in such offering. In connection with any offering of Rights, we may enter into a standby arrangement with one or more underwriters or other purchasers, pursuant to which the underwriters or other purchasers may be required to purchase any securities remaining unsubscribed for after such offering.

The prospectus supplement relating to any Rights we offer, if any, will, to the extent applicable, include specific terms relating to the offering, including some or all of the following:

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DESCRIPTION OF UNITS

We may issue units comprised of shares of common stock, shares of preferred stock and warrants in any combination. We may issue units in such amounts and in as many distinct series as we wish. This section outlines certain provisions of the units that we may issue. If we issue units, they will be issued under one or more unit agreements to be entered into between us and a unit agent. The information described in this section may not be complete in all respects and is qualified entirely by reference to the unit agreement with respect to the units of any particular series. The specific terms of any series of units offered will be described in the applicable prospectus supplement. If so described in a particular prospectus supplement, the specific terms of any series of units may differ from the general description of terms presented below. We urge you to read any prospectus supplement related to any series of units we may offer, as well as the complete unit agreement and unit certificate that contain the terms of the units. If we issue units, forms of unit agreements and unit certificates relating to such units will be incorporated by reference as exhibits to the registration statement, which includes this prospectus.

Each unit that we may issue will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date. The applicable prospectus supplement may describe:

The provisions described in this section, as well as those described under the "Description of Capital Stock," and "Description of Warrants" will apply to the securities included in each unit, to the extent relevant and as may be updated in any prospectus supplements. We may issue units in such amounts and in as many distinct series as we wish. Most of the financial and other specific terms of a particular series will be described in the applicable prospectus supplement.

We will issue the units under one or more unit agreements to be entered into between us and a unit agent. We may add, replace or terminate unit agents from time to time. We will identify the unit agreement under which each series of units will be issued and the unit agent under that agreement in the applicable prospectus supplement.

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PLAN OF DISTRIBUTION

We may sell the offered securities in and outside the United States (1) through underwriters or dealers, (2) directly to one or more purchasers, including to a limited number of institutional purchasers, to a single purchaser or to our affiliates and stockholders, (3) through agents or (4) through a combination of any of these methods.

If underwriters or dealers are used in the sale, the securities will be acquired by the underwriters or dealers for their own account and may be resold from time to time in one or more transactions, including:

The applicable prospectus supplement will set forth the following information to the extent applicable:

Sale through Underwriters or Dealers

If any securities are offered through underwriters, the underwriters will acquire the securities for their own account and may resell them from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer and sell securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless otherwise provided in the applicable prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions, and the underwriters will be obligated to purchase all of the offered securities if they purchase any of them. In connection with the sale of securities, underwriters may be deemed to have received compensation from us in the form of underwriting discounts or commissions and dealers may receive compensation from the underwriters in the form of discounts or concessions. The underwriters may change from time to time any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers.

In order to facilitate the offering of securities, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. Specifically, the underwriters may over allot in

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connection with the offering, creating a short position in the securities for their account. In addition, to cover overallotments or to stabilize the price of the shares, the underwriters may bid for, and purchase, shares in the open market. Finally, an underwriting syndicate may reclaim selling concessions allowed to an underwriter or a dealer for distributing the securities in the offering if the syndicate repurchases previously distributed shares in transactions to cover syndicate short positions, in stabilization transactions, or otherwise. Any of these activities may stabilize or maintain the market price of the offered securities above independent market levels. The underwriters are not required to engage in these activities, and may discontinue any of these activities at any time.

Some or all of the securities that we offer through this prospectus may be new issues of securities with no established trading market. Any underwriters to whom we sell securities for public offering and sale may make a market in those securities, but they will not be obligated to do so and they may discontinue any market making at any time without notice. Accordingly, we cannot assure you of the liquidity of, or continued trading markets for, any securities offered pursuant to this prospectus.

If any securities are offered through dealers, we will sell the securities to them as principals. They may then resell those securities to the public at varying prices determined by the dealers at the time of resale.

Under Rule 15c6-1 of the Exchange Act, trades in the secondary market generally are required to settle in one business day, unless the parties to any such trade expressly agree otherwise. The applicable prospectus supplement may provide that the original issue date for your securities may be more than one scheduled business day after the trade date for your securities. Accordingly, in such a case, if you wish to trade securities on any date prior to the business day before the original issue date for your securities, you will be required, by virtue of the fact that your securities initially are expected to settle in more than one scheduled business day after the trade date for your securities, to make alternative settlement arrangements to prevent a failed settlement.

Direct Sales and Sales through Agents

We may sell the securities directly to purchasers. If the securities are sold directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities, we will describe the terms of any such sales in the applicable prospectus supplement. We may also sell the securities through agents designated from time to time. Sales may be made by means of ordinary brokers' transactions on the New York Stock Exchange at market prices, in block transactions and such other transactions as agreed by us and any agent. In the applicable prospectus supplement, we will name any agent involved in the offer or sale of the offered securities, and we will describe any commissions payable to the agent. Unless otherwise provided in the applicable prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

At-the-Market Offerings

To the extent that we make sales through one or more underwriters or agents in at-the-market offerings, we will do so pursuant to the terms of a sales agency financing agreement or other at-the-market offering arrangement between us and the underwriters or agents. If we engage in at-the-market sales pursuant to any such agreement, we will issue and sell our securities through one or more underwriters or agents, which may act on an agency basis or a principal basis. During the term of any such agreement, we may sell securities on a daily basis in exchange transactions or otherwise as we agree with the underwriters or agents. Any such agreement will provide that any securities sold will be sold at prices related to the then-prevailing market prices for our securities. Therefore, exact figures regarding proceeds that will be raised or commissions to be paid cannot be determined at this time. Pursuant to the terms of the agreement, we may agree to sell, and the relevant underwriters or agents may agree to solicit offers to purchase, blocks of our common stock or other securities. The terms of any such agreement will be set forth in more detail in the applicable prospectus supplement.

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Remarketing Arrangements

Offered securities may also be offered and sold, if we so indicate in the applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to their terms, or otherwise, by one or more remarketing firms, acting as principals for their own accounts or as our agents. Any remarketing firm will be identified and the terms of its agreements, if any, with us and its compensation will be described in the applicable prospectus supplement. Remarketing firms may be deemed to be underwriters of the offered securities under the Securities Act.

Delayed Delivery Contracts

If we so indicate in the applicable prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers by certain institutions to purchase securities from us pursuant to contracts providing for payment and delivery on a specified future date. The applicable prospectus supplement will describe the conditions to those contracts and the commission payable for solicitation of those contracts.

General Information

We may have agreements with the agents, dealers, underwriters and remarketing firms to indemnify them against certain civil liabilities, including liabilities under the Securities Act, or to contribute with respect to payments that the agents, dealers or underwriters may be required to make. Agents, dealers, underwriters and remarketing firms may be customers of, engage in transactions with or perform services for us in the ordinary course of their businesses.

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LEGAL MATTERS

The validity of the securities offered by this prospectus will be passed upon for us by Goodwin Procter LLP, Redwood City, California. Any underwriters, dealers and agents will also be advised about the validity of the securities and other legal matters by their own counsel, which will be named in the prospectus supplement.

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EXPERTS

EY Han Young (formerly, Ernst & Young Han Young), independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025 and the effectiveness of our internal control over financial reporting as of December 31, 2025, as set forth in their reports, which are incorporated by reference in this prospectus and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on EY Han Young's reports, given on their authority as experts in accounting and auditing.

The financial statements as of December 31, 2024 and for the year ended December 31, 2024 incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2025 have been so incorporated in reliance on the report of Samil PricewaterhouseCoopers, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a shelf registration statement that we have filed with the SEC. This prospectus and any applicable prospectus supplement do not contain all of the information set forth in the registration statement and its exhibits and schedules in accordance with SEC rules and regulations. For further information with respect to us and the securities being offered by this prospectus and the applicable prospectus supplement, you should read the registration statement, including its exhibits and schedules. Statements contained in this prospectus and the applicable prospectus supplement, including documents that we have incorporated by reference, as to the contents of any contract or other document referred to are not necessarily complete, and, with respect to any contract or other document filed as an exhibit to the registration statement or any other such document, each such statement is qualified in all respects by reference to the corresponding exhibit. You should review the complete contract or other document to evaluate these statements. You may obtain copies of the registration statement and its exhibits via the SEC's EDGAR database or our website.

We file annual, quarterly and current reports, proxy statements and other documents with the SEC under the U.S. Securities Exchange Act of 1934, as amended, or 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 also make these documents available on our website at www.investors.magnachip.com. Our website and the information contained or connected to our website is not incorporated by reference in this prospectus or any prospectus supplement, and you should not consider it part of this prospectus or any prospectus supplement.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

SEC rules permit us to incorporate information by reference in this prospectus and the 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 the 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 the 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.

All documents that we file (but not those that we furnish) pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, after the date of the initial registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement shall be deemed to be incorporated by reference into this prospectus and will automatically update and supersede the information in this prospectus, and any previously filed documents.

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference in this prospectus or the applicable prospectus supplement shall be deemed to be modified or superseded for purposes of this prospectus and such applicable prospectus supplement to the extent that a statement contained in this prospectus or such applicable prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference in this prospectus and such applicable prospectus supplement, modifies or supersedes such earlier statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus or such applicable prospectus supplement. Nothing in this prospectus shall be deemed to incorporate information furnished but not filed with the SEC pursuant to Item 2.02 or Item 7.01 of Form 8-K.

Upon request, we will provide, without charge, to each person, including any beneficial owner, to whom a copy of this prospectus or an applicable prospectus supplement is delivered, a copy of the documents incorporated by reference into this prospectus or such prospectus supplement but not delivered with this prospectus or such prospectus supplement. You may request a copy of these filings, and any exhibits we have specifically incorporated by reference as an exhibit in this prospectus or such prospectus supplement, at no cost by writing us at the following address: c/o Magnachip Semiconductor, Ltd., 15F, 76 Jikji-daero 436beon-gil, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28581, Republic of Korea; Attention: Investor Relations; email address: [email protected] or by telephone at: +82 (2) 6903-3000.

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Up to $50,000,000

Common Stock

PROSPECTUS SUPPLEMENT

B. Riley Securities

June 17, 2026