Supplemental Prospectus (Form 424B3)

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 (the "Registration Statement") that we filed with the Securities and Exchange Commission (the "SEC") using the "shelf" registration process. Under this shelf registration process, the Selling Stockholders hereunder may, from time to time in one or more offerings, sell the shares of common stock offered by them described in this prospectus.

We have not authorized anyone to provide you with information other than the information that we have provided or incorporated by reference in this prospectus and your reliance on any unauthorized information or representation is at your own risk. This prospectus may be used only in jurisdictions where offers and sales of these securities are permitted. You should assume that the information appearing in this prospectus is accurate only as of the date on the front cover of this prospectus, any information we have incorporated by reference is accurate only as of the date of the document so incorporated and that any information in a supplement or amendment to this prospectus is accurate only as of the date of such supplement or amendment, in each case regardless of the time of delivery of this prospectus, or any sale of the shares. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus and the information incorporated herein by reference contain summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below in the section titled "Where You Can Find Additional Information."

Unless otherwise stated, all references in this prospectus to "we," "us," "our," "the Company," "NN," and similar designations, except where the context requires otherwise, refer collectively to NN, Inc. and its subsidiaries. Our name "NN," the NN logo and other trademarks or service marks of NN, Inc. appearing in this prospectus and in any prospectus supplement or free writing prospectus and the information incorporated by reference herein or therein are the property of NN, Inc. Other trademarks, service marks or trade names appearing in this prospectus in any prospectus supplement or free writing prospectus and the information incorporated by reference herein or therein are the property of their respective owners. We do not intend our use or display of other companies' trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of us by, these other companies.

our most recently completed second fiscal quarter in our last completed fiscal year or (ii) our annual revenue was less than $100 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700 million. Specifically, as a smaller reporting company, we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and are subject to reduced disclosure obligations regarding executive compensation.

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading "Risk Factors" contained in any applicable prospectus supplement and any related free writing prospectus, and under similar headings in our most recent Annual Report on Form 10-K, as updated by our subsequent annual, quarterly and other reports and documents that are incorporated by reference into this prospectus and any applicable prospectus supplement before deciding whether to purchase any of our securities being registered pursuant to the registration statement of which this prospectus is a part. Each of the risk factors described in the documents referenced above could adversely affect our business, operating results, and financial condition, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial, may also significantly impair our business operations. Please also read carefully the section below titled "Special Note Regarding Forward-Looking Statements."

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, each applicable prospectus supplement, and the information incorporated by reference in this prospectus and each prospectus supplement contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act"), and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), which are intended to be covered by the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and include this statement for purposes of complying with these safe harbor provisions. Forward-looking statements generally will be accompanied by words such as "anticipate," "believe," "could," "estimate," "expect," "forecast," "growth," "guidance," "intend," "may," "possible," "potential," "predict," "project," "trajectory," "will" or the negative of those terms, and similar expressions that convey uncertainty of future events or outcomes. Forward-looking statements involve a number of risks and uncertainties that are outside of management's control and that may cause actual results to be materially different from such forward-looking statements. Such factors include, among others, general economic conditions and economic conditions in the industrial sector; competitive influences; risks that current customers will commence or increase captive production; risks of capacity underutilization; quality issues; inflationary pressures and material changes in the cost or availability of raw materials, supply chain shortages and disruptions, the availability of labor and labor disruptions along the supply chain; our dependence on certain major customers, some of whom are not parties to long-term agreements (and/or are terminable on short notice); the impact of acquisitions and divestitures, as well as expansion of end markets and product offerings; our ability to hire or retain key personnel; the restrictions contained in our debt agreements; the level of our indebtedness and our ability to obtain financing at favorable rates, if at all, or to refinance existing debt as it matures; our ability to secure, maintain or enforce patents or other appropriate protections for our intellectual property; the impact of climate change on our operations; economic, social, political and geopolitical instability, military conflict, currency fluctuation, and other risks of doing business outside of the United States; uncertainty of government policies and actions in respect to global trade and tariffs, including the potential impacts of tariffs on the United States economy, the economy of other countries in which we conduct operations and our industry; cyber liability or potential liability for breaches of our or our service providers' information technology systems or business operations disruptions; and other risks and uncertainties set forth in documents filed, or to be filed, with the SEC. For the reasons described above, we caution against relying on any forward-looking statements, which should also be read in conjunction with the sections entitled "Business," "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and in other sections incorporated by reference from our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, as applicable, as well as our other filings with the SEC. You should be aware that the occurrence of any of the events discussed under the heading "Risk Factors" in any applicable prospectus supplement and any documents incorporated by reference herein or therein could substantially harm our business, operating results, and financial condition and that if any of these events occurs, it could adversely affect the value of an investment in our securities.

The cautionary statements made in this prospectus are intended to be applicable to all related forward-looking statements wherever they may appear in this prospectus or in any prospectus supplement or any documents incorporated by reference herein or therein. We urge you not to place undue reliance on these

USE OF PROCEEDS

We will not receive any of the proceeds from the sale or other disposition of shares of our common stock held by the Selling Stockholders pursuant to this prospectus. We will receive nominal proceeds from the exercise of the Pre-Funded Warrants if such warrants are exercised for cash at the exercise price of $0.01 per share. We will bear the out-of-pocket costs, expenses and fees incurred in connection with the registration of shares of our common stock to be sold by the Selling Stockholders pursuant to this prospectus. Other than registration expenses, the Selling Stockholders will bear underwriting discounts, commissions, placement agent fees or other similar expenses payable with respect to sales of shares of our common stock.

DESCRIPTION OF CAPITAL STOCK

General

Our authorized capital stock consists of 185,000,000 shares, consisting of 180,000,000 shares of common stock, $0.01 par value per share, and 5,000,000 shares of preferred stock, $0.01 par value per share ("Preferred Stock"). Our board of directors (the "Board") is authorized, without stockholder approval, except as required by the listing standards of the Nasdaq Stock Market, to issue additional shares of our capital stock. In addition, our board of directors may, without further action by our stockholders, designate the rights, preferences, privileges, and restrictions of our Preferred Stock in one or more series.

As of October 7, 2026, we had outstanding 93,744,210 shares of common stock.

Common Stock

The following description of common stock is a summary and is qualified in its entirety by reference to the actual terms and provisions contained in our Restated Certificate of Incorporation, as amended from time to time (the "Certificate of Incorporation"), and our Amended and Restated Bylaws, as amended from time to time (the "Bylaws"), each of which is filed as an exhibit to the registration statement of which this prospectus is a part. We encourage you to read our Certificate of Incorporation, our Bylaws, and the applicable provisions of the Delaware General Corporation Law ("DGCL") for additional information.

Dividends

Subject to preferential rights of any other class or series of Preferred Stock, holders of common stock may receive dividends pro rata out of assets that we can legally use to pay dividends, when, as and if they are declared by our Board.

Voting Rights

Holders of common stock will have the exclusive power to vote on all matters presented to our stockholders, including the election of directors, except as otherwise provided by Delaware law or as provided with respect to any other class or series of stock. Holders of common stock are entitled to one vote per share. There is no cumulative voting in the election of our directors, which means that, subject to any rights to elect directors that are granted to the holders of any class or series of Preferred Stock, a majority of the votes cast at a meeting of stockholders at which a quorum is present is required to elect a director in any uncontested election and a plurality of the votes cast at a meeting of stockholders at which a quorum is present is required to elect a director in any contested election.

Liquidation Rights

In the event we are liquidated, dissolved or our affairs are wound up, after we pay or make adequate provision for all of our known debts and liabilities, each holder of common stock will receive dividends pro rata out of assets that we can legally use to pay distributions, subject to any rights that are granted to the holders of any class or series of Preferred Stock.

Fully Paid and Nonassessable

The outstanding shares of our common stock are fully paid and nonassessable.

Absence of Other Rights

Holders of common stock have no preference, appraisal or exchange rights, except for any appraisal rights provided by Delaware law. Furthermore, holders of common stock have no conversion, sinking fund or redemption rights, or preemptive rights to subscribe for any of our securities.

Preferred Stock

Our Certificate of Incorporation authorizes our Board, without stockholder approval, to designate and issue up to 5,000,000 shares of Preferred Stock, in one or more series and to fix the rights, preferences,

privileges and restrictions granted to or imposed upon each such series of Preferred Stock, including voting rights, dividend rights, conversion rights, terms of redemption, liquidation preference, sinking fund terms, subscription rights and the number of shares constituting any series or the designation of a series. Our Board can issue, without stockholder approval, Preferred Stock with voting and conversion rights that could adversely affect the voting power of the holders of common stock and reduce the likelihood that such holders will receive dividend payments or payments upon liquidation. Such issuance could have the effect of decreasing the market price of the common stock. The issuance of Preferred Stock or even the ability to issue Preferred Stock could also have the effect of delaying, deterring or preventing a change of control or other corporate action. There are currently no issued and outstanding shares of Preferred Stock.

Warrants

As of October 5, 2026, there were Pre-Funded Warrants to purchase up to 4,824,395 shares of common stock at an exercise price of $0.01 per share outstanding, which are exercisable at any time until exercised in full. In addition, as of October 5, 2026, there were warrants to purchase up to 1,215,000 shares of common stock at an exercise price of $11.03 per share outstanding, which are exercisable, in full or in part, at any time prior to December 11, 2026.

Pre-Funded Warrants

In connection with the Private Placement, we issued Pre-Funded Warrants to purchase 4,824,395 shares of common stock. The Pre-Funded Warrants have an exercise price of $0.01 per share, are immediately exercisable, and may be exercised at any time until exercised in full. The Pre-Funded Warrants may be exercised on a cashless basis. The exercise price and number of shares of common stock issuable upon exercise of the Pre-Funded Warrants are subject to adjustment for stock splits, stock dividends, reclassifications and similar events.

A holder of a Pre-Funded Warrant may not exercise the warrant to the extent that, after giving effect to the exercise, such holder (together with its affiliates and any other persons acting as a group together with such holder) would beneficially own more than 4.99% (or, at the election of the holder at the time of issuance, 9.99%) of the outstanding shares of our common stock. A holder may increase or decrease this limitation upon 61 days' prior notice to us. However, a holder of a Pre-Funded Warrant may not exercise the warrant to the extent that, after giving effect to the exercise, such holder (together with its affiliates and any other persons acting as a group together with such holder) would beneficially own more than 19.99% of the outstanding shares of our common stock, which beneficial ownership limitation may not be amended or waived by the holder or the Company unless and until stockholder approval is obtained in accordance with Nasdaq Listing Rule 5635(b).

Delaware Anti-Takeover Statute

We are subject to the provisions of Section 203 of the DGCL regulating corporate takeovers. In general, Section 203, subject to certain exceptions, prohibits a publicly held Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years following the date that such person or entity became an interested stockholder, unless:

•

prior to such date, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

​

•

upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding specified shares; or

​

•

at or subsequent to such date of the transaction that resulted in a person or entity becoming an interested stockholder, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 662∕3% of the outstanding voting stock that is not owned by the interested stockholder.

​

The application of Section 203 may limit the ability of stockholders to approve a transaction that they may deem to be in their best interests. In addition, Section 203 makes it more difficult for an interested

stockholder to effect various business combinations with a corporation for a three-year period, although the stockholders may, by adopting an amendment to our Certificate of Incorporation or Bylaws, elect not to be governed by this section, effective 12 months after adoption.

In general, Section 203 defines "business combination" as:

•

any merger or consolidation involving the corporation and the interested stockholder;

​

•

any sale, lease, exchange, mortgage, pledge, transfer or other disposition of 10% or more of the assets of the corporation to or with the interested stockholder;

​

•

subject to certain exceptions, any transaction which results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

​

•

any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or

​

•

the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

​

In general, Section 203 defines an "interested stockholder" as any person that is:

•

the owner of 15% or more of the outstanding voting stock of the corporation;

​

•

an affiliate or associate of the corporation and was the owner of 15% or more of the outstanding voting stock of the corporation at any time within three years immediately prior to the relevant date; or

​

•

an affiliate or associate of the above.

​

Our Certificate of Incorporation and Bylaws do not exclude us from the restrictions imposed under Section 203. We anticipate that the provisions of Section 203 may encourage companies interested in acquiring us to negotiate in advance with our board of directors because the stockholder approval requirement would be avoided if a majority of the directors then in office approve either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder.

Other Corporate Governance Matters

Under our Certificate of Incorporation, directors shall be elected for a one-year term expiring at the next annual meeting. Directors elected to succeed those directors whose terms then expire shall be elected for a term of office to expire at the succeeding annual meeting after their election, with each director to hold office until his or her successor shall have been duly elected and qualified.

Subject to the preferential rights of any other class or series of preferred stock, any director, or the entire Board, may be removed from office at any time, with or without cause, by the affirmative vote of the holders of a majority of the voting power of all the then outstanding shares of voting stock of the Company, voting together as a single class. Our Bylaws require that stockholders provide the Secretary of our company with notice of the nomination of a person for election as a director with respect to an election to be held at an annual meeting of stockholders, not less than 90 nor more than 120 days prior to the anniversary date of the immediately preceding annual meeting of stockholders or special meeting in lieu of an annual meeting, provided, however, that if the date of the annual meeting is more than 30 days before or more than 60 days after such anniversary date, notice by the stockholder to be timely must be given, not earlier than the 120th day prior to such annual meeting and not later than the 90th day prior to such annual meeting or, if later, the 10th day following the day on which public disclosure of the date of such annual meeting was first made. To be timely, a stockholder's notice for nominations to be made at a special meeting must be made not earlier than the 120th day prior to such special meeting and not later than the 90th day prior to such special meeting or, if later, the 10th day following the day on which public disclosure of the date of such special meeting was first made. Our Bylaws provide that special meetings of stockholders of our company may be called only by: (i) the Chairman of the Board, (ii) by a majority of the Board, or (iii) the Chief Executive Officer of our Company. Our Certificate of Incorporation, as well as applicable provisions of the DGCL, provide that no action required or permitted to be taken at any annual or special meeting of our stockholders

may be taken without a meeting, unless the consent of two-thirds of the voting power of the then outstanding shares of stock of the company entitled to vote on the matter is obtained. These provisions may diminish the likelihood that a potential acquirer would make an offer for our common stock or that there would otherwise be a change in control of our company.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent's address is 462 South 4th Street, Louisville, Kentucky 40202.

Listing

Our common stock is listed on the Nasdaq Stock Market under the trading symbol "NNBR."

SELLING STOCKHOLDERS

The Selling Stockholders may sell some, all or none of their shares. We do not know how long the Selling Stockholders will hold the shares before selling them, and we currently have no agreements, arrangements or understandings with the Selling Stockholders regarding the sale or other disposition of any of the shares. The shares covered hereby may be offered from time to time by the Selling Stockholders. As a result, we cannot estimate the number of shares of common stock the Selling Stockholders will beneficially own after termination of sales under this prospectus. In addition, the Selling Stockholders may have sold, transferred or otherwise disposed of all or a portion of their shares of common stock since the date on which they provided information for the table below.

Information regarding each additional Selling Stockholder, if any, will be set forth by a prospectus supplement to the extent required prior to the time of any offer or sale of such Selling Stockholder's shares pursuant to this prospectus. Any prospectus supplement may add, update, substitute, or change the information contained in this prospectus, including the identity of each Selling Stockholder and the number of shares registered on its behalf. A Selling Stockholder may sell or otherwise transfer all, some or none of such shares in this offering. See "Plan of Distribution."

Beneficial ownership is determined in accordance with the rules of the SEC and includes voting or investment power with respect to our common stock. Generally, a person "beneficially owns" shares of our common stock if the person has or shares with others the right to vote those shares or to dispose of them, or if the person has the right to acquire voting or disposition rights within 60 days.

The information in the table below and the footnotes thereto regarding shares of common stock to be beneficially owned after the offering assumes the sale of all shares being offered by the Selling Stockholders under this prospectus. This information has been obtained from the Selling Stockholders. The percentage of shares owned after the offering is based on 93,744,210 shares of common stock outstanding as of October 7, 2026. In computing the number of shares of common stock beneficially owned by a Selling Stockholder and the percentage ownership of that Selling Stockholder, we deemed outstanding shares of common stock subject to Pre-Funded Warrants or other options, warrants or convertible securities held by that Selling Stockholder that are currently exercisable or exercisable within 60 days of October 7, 2026. We did not deem these shares outstanding, however, for the purpose of computing the percentage ownership of any other Selling Stockholder.

Except for the ownership of shares of our common stock and Pre-Funded Warrants issued pursuant to the Purchase Agreement and the registration rights granted pursuant to the Registration Rights Agreement, none of the Selling Stockholders has had any material relationship with us or any of our predecessors or affiliates within the past three years. None of the Selling Stockholders is a broker-dealer or an affiliate of a broker-dealer.

​

*

Less than 1%

​

(1)

Includes 6,647,441 shares of common stock and 2,400,000 pre-funded warrants, which exercise is limited such that holder's beneficial ownership may not exceed 9.99%. Mr. Orin Hirschman is the managing member of AIGH Capital Management, LLC, a Maryland limited liability company ("AIGH CM"), which is an advisor with respect to securities held by AIGH Investment Partners, LP ("AIGH LP"). Mr. Hirschman has voting and investment control over the securities indirectly held by AIGH CM, directly held by AIGH LP and directly held by Mr. Hirschman and his family. The address for AIGH CM, AIGH LP and Mr. Hirschman is 6006 Berkeley Avenue, Baltimore, Maryland 21209.

​

(2)

Includes 2,279,546 shares of common stock and 750,000 pre-funded warrants, which exercise is limited such that holder's beneficial ownership may not exceed 9.99%. Mr. Orin Hirschman is the managing member of AIGH CM, who is a sub-advisor with respect to securities held by WVP Emerging Manager Onshore Fund, LLC - AIGH Series. Mr. Hirschman has voting and investment control over the securities indirectly held by AIGH CM and directly held by Mr. Hirschman and his family directly. The address for AIGH CM and Mr. Hirschman is 6006 Berkeley Avenue, Baltimore, Maryland 21209.

​

(3)

Includes 4,524,637 shares of common stock and reflects 1,674,395 pre-funded warrants, which exercise is limited such that holder's beneficial ownership may not exceed 4.99%. Alyeska Investment Group, L.P., the investment manager of Alyeska Master Fund, L.P., has voting and investment control of the shares held by Alyeska Master Fund, L.P. Anand Parekh is the Chief Executive Officer of Alyeska Investment Group, L.P. and may be deemed to be the beneficial owner of such shares. Mr. Parekh, however, disclaims any beneficial ownership of the shares held by Alyeska Master Fund, L.P., other than to the extent of any pecuniary interest therein. The registered address of Alyeska Master Fund, L.P. is at c/o Maples Corporate Services Limited, P.O. Box 309, Ugland House, South Church Street George Town, Grand Cayman, KY1-1104, Cayman Islands. Alyeska Investment Group, L.P. is located at 77 W. Wacker, Suite 700, Chicago IL 60601.

​

(4)

Polar Long/Short Master Fund and Polar Multi-Strategy Master Fund (each referred to as "Polar") are under management by Polar Asset Management Partners Inc. ("PAMPI"). PAMPI serves as investment advisor of Polar and has control and discretion over the shares held by Polar. As such, PAMPI may be deemed the beneficial owner of the shares held by Polar. PAMPI disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest therein. John Paul Sabourin, in his capacity as Chief Investment Officer of PAMPI, may also be deemed the beneficial owner of the shares held by Polar. Mr. Sabourin disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest therein. The principal business address of Polar is 94 Solaris Avenue, Camana Bay, PO Box 1348, Grand Cayman KY1-1108, Cayman Islands.

​

(5)

Laurence Lytton may be deemed to have voting and dispositive power with respect to the common shares beneficially owned by the Lytton-Kambara Foundation. The address of Lytton-Kambara Foundation is 467 Central Park West 17-A, New York, NY 10025, Attn: Laurence Lytton, Managing Partner.

​

(6)

AWM Investment Company, Inc. ("AWM") is the investment adviser to each of the Special Situations Funds. David Greenhouse and Adam Stettner are the principal owners of AWM. Through their control

​

of AWM, Messrs. Greenhouse and Stettner share voting and investment control over the portfolio securities of each of the Special Situations Funds. Messrs. Greenhouse and Stettner disclaim any beneficial ownership of the reported shares other than to the extent of any pecuniary interest each of them may have therein. The address of AWM, each of the Funds and Messrs. Greenhouse and Stettner is 527 Madison Avenue, Suite 2600, New York, NY 10022.

(7)

Includes 256,515 shares of common stock held by Empery Asset Master Ltd ("EAM"), 120,499 shares of common stock held by Empery Tax Efficient, LP ("ETE") and 192,683 shares of common stock held by Empery Tax Efficient III, LP ("ETE III" and collectively with EAM and ETE, the "Empery Funds"). Empery Asset Management LP, the authorized agent of each of the Empery Funds, has discretionary authority to vote and dispose of the shares held by the Empery Funds and may be deemed to be the beneficial owner of these shares. Ryan Lane, in his capacity as the chief investment officer of Empery Asset Management LP, may also be deemed to have investment discretion and voting power over the shares held by the Empery Funds. Each of the Empery Funds and Mr. Lane each disclaim any beneficial ownership of these shares. The address of each of the Empery Funds is c/o Empery Asset Management, LP, One Rockefeller Plaza, Suite 1205, New York, NY 10020.

​

(8)

William Mueller may be deemed to have voting and dispositive power with respect to the common shares beneficially owned by Mink Brook Partners LP and Mink Brook Opportunity Fund LP. The address of Mink Brook Partners LP and Mink Brook Opportunity Fund LP is 201 Summa Street, West Palm Beach, FL 33405, Attn: William Mueller.

​

(9)

Carl Wiese may be deemed to have voting and dispositive power with respect to the common shares beneficially owned by GROW Small Cap Equity Long Short LP. The address of GROW Small Cap Equity Long Short LP is 4275 Executive Square, Suite 335, La Jolla, CA 92037.

​

(10)

W. Patrick Schubmehl may be deemed to have voting and investment control over the portfolio securities held by WPS Direct Fund and WPS Capital Fund. Mr. Schubmehl disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest he may have therein. The address of each of WPS Direct Fund and WPS Capital Fund is 6641 West Broad Street, Suite 600, Richmond, VA 23230.

​

(11)

Roger Porter may be deemed to have voting and investment control over the portfolio securities held by TSW Small Cap Opportunities Fund, a series of TSW Fund Management Company LLC. Mr. Porter disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest he may have therein. The address of TSW Small Cap Opportunities Fund, a series of TSW Fund Management Company LLC is 6641 West Broad Street, Suite 600, Richmond, VA 23230.

​

(12)

Strategos Master Fund, L.P. and Strategos Fund, L.P. are managed by Archon Capital Management LLC, and may be deemed to have discretionary authority to vote and dispose of the shares held by such funds. Constantinos Christofilis in his capacity as Managing Member of Archon Capital Management LLC, may also be deemed to have investment discretion and voting power over the shares held by Strategos Master Fund, L.P. and Strategos Fund, L.P.. Each of the Archon Capital Management LLC and Mr. Christofilis each disclaim any beneficial ownership of such shares. The address of each fund is 1100 19th Avenue East, Seattle WA 98112.

​

PLAN OF DISTRIBUTION

Each Selling Stockholder of the securities and any of their pledgees, assignees and successors-in-interest may, from time to time, sell any or all of their securities covered hereby on any stock exchange, market or trading facility on which the securities are traded or in private transactions. These sales may be at fixed or negotiated prices. A Selling Stockholder may use any one or more of the following methods when selling securities:

•

ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

​

•

block trades in which the broker-dealer will attempt to sell the securities as agent but may position and resell a portion of the block as principal to facilitate the transaction;

​

•

purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

​

•

an exchange distribution in accordance with the rules of the applicable exchange;

​

•

privately negotiated transactions;

​

•

settlement of short sales;

​

•

in transactions through broker-dealers that agree with the Selling Stockholders to sell a specified number of such securities at a stipulated price per security;

​

•

through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;

​

•

a combination of any such methods of sale; or

​

•

any other method permitted pursuant to applicable law.

​

The Selling Stockholders may also sell securities under Rule 144 or any other exemption from registration under the Securities Act, if available, rather than under this prospectus.

Broker-dealers engaged by the Selling Stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the Selling Stockholders (or, if any broker-dealer acts as agent for the purchaser of securities, from the purchaser) in amounts to be negotiated, but, except as set forth in a supplement to this Prospectus, in the case of an agency transaction not in excess of a customary brokerage commission in compliance with FINRA Rule 2121; and in the case of a principal transaction a markup or markdown in compliance with FINRA Rule 2121.

In connection with the sale of the securities or interests therein, the Selling Stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the securities in the course of hedging the positions they assume. The Selling Stockholders may also sell securities short and deliver these securities to close out their short positions, or loan or pledge the securities to broker-dealers that in turn may sell these securities. The Selling Stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or create one or more derivative securities which require the delivery to such broker-dealer or other financial institution of securities offered by this prospectus, which securities such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

The Selling Stockholders and any broker-dealers or agents that are involved in selling the securities may be deemed to be "underwriters" within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the securities purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. Each Selling Stockholder has informed the Company that it does not have any written or oral agreement or understanding, directly or indirectly, with any person to distribute the securities.

The Company is required to pay certain fees and expenses incurred by the Company incident to the registration of the securities. The Company has agreed to indemnify the Selling Stockholders against certain losses, claims, damages and liabilities, including liabilities under the Securities Act.

We agreed to keep the registration statement of which this prospectus is a part effective until the earlier of (i) the date on which the securities may be resold by the Selling Stockholders without registration and

without regard to any volume or manner-of-sale limitations by reason of Rule 144, without the requirement for the Company to be in compliance with the current public information under Rule 144 under the Securities Act or any other rule of similar effect or (ii) all of the securities have been sold pursuant to this prospectus or Rule 144 under the Securities Act or any other rule of similar effect. The resale securities will be sold only through registered or licensed brokers or dealers if required under applicable state securities laws. In addition, in certain states, the resale securities covered hereby may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and is complied with.

Under applicable rules and regulations under the Exchange Act, any person engaged in the distribution of the resale securities may not simultaneously engage in market making activities with respect to the shares of common stock for the applicable restricted period, as defined in Regulation M, prior to the commencement of the distribution. In addition, the Selling Stockholders will be subject to applicable provisions of the Exchange Act and the rules and regulations thereunder, including Regulation M, which may limit the timing of purchases and sales of the shares of common stock by the Selling Stockholders or any other person. We will make copies of this prospectus available to the Selling Stockholders and have informed them of the need to deliver a copy of this prospectus to each purchaser at or prior to the time of the sale (including by compliance with Rule 172 under the Securities Act).

LEGAL MATTERS

Dentons US LLP New York, New York, will pass upon the validity of the shares of common stock offered hereby.

EXPERTS

The audited financial statements and management's assessment of the effectiveness of internal control over financial reporting incorporated by reference in this prospectus and elsewhere in the registration statement have been so incorporated by reference in reliance upon the reports of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

This prospectus is part of a registration statement on Form S-3 we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website at www.sec.gov that contains reports, proxy and information statements, and other information regarding issuers, such as us, that file electronically with the SEC.

Copies of certain information filed by us with the SEC are also available on our website at www.nninc.com. Information contained in or accessible through our website does not constitute a part of this prospectus and is not incorporated by reference in this prospectus. We have included our website address as an inactive textual reference only.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to "incorporate by reference" information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The documents incorporated by reference into this prospectus contain important information that you should read about us.

The following documents are incorporated by reference into this document (other than Current Reports or portions thereof furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items and other portions of documents that are furnished, but not filed, or are otherwise not incorporated into registration statements pursuant to applicable rules promulgated by the SEC):

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 4, 2026;

​

•

the information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 from our definitive proxy statement on Schedule 14A, filed with the SEC on April 6, 2026;

​

•

our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026, filed with the SEC on May 6, 2026;

​

•

our Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026, filed with the SEC on August 5, 2026;

​

•

our Current Reports on Form 8-K (other than information furnished rather than filed), filed with the SEC on January 20, 2026, January 30, 2026, May 20, 2026, June 12, 2026, July 1, 2026, July 23, 2026, July 24, 2026, July 31, 2026, September 30, 2026, October 5, 2026 and October 8, 2026; and

​

•

the description of our common stock, which is registered under Section 12 of the Exchange Act, described in Exhibit 4.5 to our Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on March 15, 2021, including any amendments or reports filed for the purposes of updating such description.

​

We also incorporate by reference into this prospectus all documents (other than Current Reports or portions thereof furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items and other portions of documents that are furnished, but not filed, or are otherwise not incorporated into registration statements pursuant to applicable rules promulgated by the SEC) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus but prior to the termination of the offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents by writing us at NN, Inc., 6210 Ardrey Kell Road, Suite 120, Charlotte, North Carolina 28277 Attention: Secretary or telephoning us at (980) 264-4300.

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.