UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.__)No. )

Filed by the Registrant ☒

Filed by a party other than the Registrant ☐

Check the appropriate box:

EQUILLIUM, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

EQUILLIUM, INC.

2223 Avenida De La Playa, Suite 105

La Jolla, CA 92037

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

Virtual Meeting Only – No Physical Meeting Location

To Be Held On May 22, 20232024

Dear Stockholder:

You are cordially invited to attend the 20232024 annual meeting of stockholders (the “Annual Meeting”) of Equillium, Inc., a Delaware corporation (the “Company”). The meeting will be held on Monday,Wednesday, May 22, 2023,2024, starting at 9:1:00 a.m.p.m. (Pacific Time). The Annual Meeting will be a virtual stockholder meeting of stockholders, which will be conducted via live webcastaudio webcast. You will be able to attend the Annual Meeting, submit your questions and vote online during the meeting by visiting www.proxydocs.com/EQ. A complete list of record stockholders will be available for examination by any stockholder for any purpose germane to the Annual Meeting for a period of ten days ending on the day before the Annual Meeting date. If you would like to view the list, please email us at www.proxydocs.com/EQ,ir@equilliumbio.com. The meeting will be held for the following purposes:

These items of business are more fully described in the Proxy Statement accompanying this Notice.

The Annual Meeting will be held virtually viathrough a live audio webcast. Stockholders of record at the Internet, please visit www.proxydocs.com/EQ. In order to attend, you must register in advance at www.proxydocs.com/EQ prior to the deadlineclose of May 21, 2023 at 5:00 p.m. (Eastern Time). Upon completing your registration, youbusiness on April 1, 2024 and their proxy holders will receive further instructions via email, including your unique link that will allow you access to the meeting and to submit questions during the meeting. You will not be able to attend the Annual Meeting, submit questions and vote during the live audio webcast by visiting www.proxydocs.com/EQ and entering the Control Number included in person.

EQUILLIUM, INC.

2223 Avenida De La Playa, Suite 105

La Jolla, CA 92037

PROXY STATEMENT

FOR THE 20232024 ANNUAL MEETING OF STOCKHOLDERS

Virtual Meeting Only – No Physical Meeting Location

To Be Held On May 22, 20232024

This proxy statement (the “Proxy Statement”) and our annual report for the fiscal year ended December 31, 20222023 (the “Annual Report” and, together with this Proxy Statement, the “proxy materials”) are being furnished by and on behalf of the board of directors (the “Board” or “Board of Directors”) of Equillium, Inc. (the “Company,” “Equillium,” “we,” “us,” or “our”), in connection with our 20232024 annual meeting of stockholders (the “Annual Meeting”). The Notice of Annual Meeting and this Proxy Statement are first being distributed or made available, as the case may be, on or about April 11, 2023.2024.

MEETING AGENDA

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TABLE OF CONTENTS

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QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING

How do I attend the Annual Meeting?

The Annual Meeting will be held via live webcast on Monday, May 22, 2023, starting at 9:00 a.m. (Pacific Time). Stockholders may attend the Annual Meeting by registering at www.proxydocs.com/EQ. This meeting will be completely virtual and will only be conducted via live webcast. There will be no physical meeting location. Stockholders may vote and submit questions while connected to the Annual Meeting.

In order to attend the Annual Meeting, you must register in advance at www.proxydocs.com/EQ prior to the deadline of May 21, 2023 at 5:00 p.m. (Eastern Time). Upon completing your registration, you will receive further instructions via email, including your unique link that will allow you access to the Annual Meeting and to submit questions during the meeting. Please be sure to follow instructions found on your proxy card and/or voting authorization form and subsequent instructions that will be delivered to you via email.

Why did I receive a notice in the mail regarding the Internet availability of proxy materials instead of a paper copy of proxy materials?

ThePursuant to rules ofadopted by the Securities and Exchange Commission (the “SEC”) permit us, we have elected to furnishprovide access to our proxy materials including this Proxy Statement andover the Annual Report, to our stockholders by providing access to such documents on the Internet instead of mailing printed copies. Stockholders will not receive paper copies of the proxy materials unless they request them. Instead, theinternet. Accordingly, we have sent you a Notice of Internet Availability of Proxy Materials (the “Notice and Access Card”“Notice”) provides instructionsbecause the Board of the Company is soliciting your proxy to vote at the 2024 Annual Meeting of Stockholders, including at any adjournments or postponements of the meeting. All stockholders will have the ability to access the proxy materials on the website referred to in the Notice or request to receive a printed set of the proxy materials. Instructions on how to access and review on the Internet all of the proxy materials. The Notice and Access Card also instructs you asmaterials over the internet or to howrequest a printed copy may be found in the Notice.

We intend to authorize via the Internet or telephone your proxy to vote your shares according to your voting instructions. If you would like to receive a paper or email copy of our proxy materials, you should follow the instructions for requesting such materials described infirst mail the Notice and Access Card.make this Proxy Statement and the form of proxy available to stockholders on or about April 11, 2024.

Will I receive any other proxy materials by mail?

We may send you a proxy card, along with a second Notice, and Access Card, on or after April 21, 2023.22, 2024.

How do I attend the Annual Meeting?

This year’s Annual Meeting will be a virtual meeting, which will be conducted entirely online via audio webcast to allow greater participation. You may attend, vote and ask questions at the Annual Meeting by following the instructions provided on the Notice or proxy card to log in to www.proxydocs.com/EQ. If you are a stockholder of record, you will be asked to provide the control number from your Notice or proxy card. If you are a beneficial owner of shares registered in the name of your broker, bank or other agent, follow the instructions from your broker or bank.

The audio webcast of the Annual Meeting will begin promptly at 1:00 p.m. Pacific Time. We encourage you to access the meeting prior to the start time. Online check-in will begin at 12:45p.m. Pacific Time, and you should allow reasonable time for the check-in procedures.

You are entitled to attend the Annual Meeting if you were a stockholder as of the close of business on April 1, 2024, the record date, or hold a valid proxy for the meeting. To be admitted to the Annual Meeting, you will need to visit www.proxydocs.com/EQ and enter the Control Number found next to the label “Control Number” on your Notice or proxy card, or in the email sending you the Proxy Statement. If you are a beneficial stockholder, you should contact the bank, broker or other institution where you hold your account well in advance of the meeting if you have questions about obtaining your control number/proxy to vote.

Whether or not you participate in the Annual Meeting, it is important that you vote your shares.

What if I cannot find my Control Number?

Please note that if you do not have your Control Number and you are a registered stockholder, you will be able to login as a guest. To view the meeting webcast visit www.proxydocs.com/EQ and register as a guest. If you login as a guest, you will not be able to vote your shares or ask questions during the meeting.

If you are a beneficial owner (that is, you hold your shares in an account at a bank, broker or other holder of record), you will need to contact that bank, broker or other holder of record to obtain your Control Number prior to the Annual Meeting.

Where can we get technical assistance if we are having trouble accessing the meeting or during the meeting?

If you have difficulty accessing the meeting or during the meeting, please refer to the technical support telephone number posted on the virtual meeting website login page, where technicians will be available to help you.

For the Annual Meeting, how do we ask questions of management and the Board?

Stockholders may submit questions relevant to the proposals to be voted on at the Annual Meeting for approximately five days in advance of the Annual Meeting through www.proxydocs.com/EQ. We plan to spend up to 15 minutes answering appropriate stockholder questions after the proposals are formally presented and prior to the closing of voting at the Annual Meeting and will include as many stockholder questions that comply with the rules of conduct for the Annual Meeting as the allotted time permits. If we receive substantially similar questions, we will group such questions together and provide a single response to avoid repetition. Questions that are not relevant to the proposals to be voted on at the Annual Meeting and not in compliance with the rules of conduct for the Annual Meeting will not be responded to. Questions may be submitted during the Annual Meeting through www.proxydocs.com/EQ.

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What does it mean if I receive more than oneWho can vote at the Annual Meeting?

Only stockholders of record at the close of business on April 1, 2024 will be entitled to vote at the Annual Meeting. On this record date, there were 35,254,752 shares of common stock outstanding and entitled to vote.

Stockholder of Record: Shares Registered in Your Name

If, on April 1, 2024, your shares were registered directly in your name with Equillium’s transfer agent, Equiniti Trust Company, LLC (f/k/a American Stock Transfer & Trust Company, LLC), then you are a stockholder of record. As a stockholder of record, you may vote online during the Annual Meeting or vote by proxy. Whether or not you plan to register and attend the Annual Meeting, we urge you to fill out and return the proxy card that you may request or that we may elect to deliver at a later time to ensure your vote is counted.

Beneficial Owner: Shares Registered in the Name of a Broker or Bank

If on April 1, 2024,your shares were held, not in your name, but rather in an account at a brokerage firm, bank or other similar organization, then you are the beneficial owner of shares held in “street name” and the Notice shouldbe forwarded to you by that organization. The organization holding your account is considered to be the stockholder of record for purposes of voting at the Annual Meeting. As a beneficial owner, you have the right to direct your broker, bank or other agent regarding how to vote the shares in your account. You must follow the instructions provided by your brokerage firm, bank, or other similar organization for your bank, broker or other stockholder of record to vote your shares per your instructions. Alternatively, many brokers and Access Cardbanks provide the means to grant proxies or more than one set of proxy materials?

It means thatotherwise instruct them to vote your shares by telephone and via the Internet, including by providing you with a control number via email or on your Notice or your voting instruction form. If your shares are held in more than onean account with a broker, bank or other stockholder of record providing such a service, you may instruct them to vote your shares by telephone (by calling the number provided in the proxy materials) or over the Internet as instructed by your broker, bank or other stockholder of record. If you did not receive a control number via email or on your Notice or voting instruction form, and you wish to vote prior to or at the transfer agent and/virtual Annual Meeting, you must follow the instructions from your broker, bank or withother stockholder of record, including any requirement to obtain a valid legal proxy. Many brokers, banks and other stockholders of record allow a beneficial owner to obtain a valid legal proxy either online or brokers. Please vote allby mail, and we recommend that you contact your broker, bank or other stockholder of your shares. To ensure that all of your shares are voted, for each Notice and Access Card or set of proxy materials, please submit your proxy by phone, via the Internet, or, if you received printed copies of the proxy materials, by signing, dating and returning the proxy card in the envelope provided.record to do so.

Can I vote my shares by filling out and returning the Notice and Access Card?Notice?

No. The Notice and Access Card identifies the items to be voted on at the Annual Meeting, but you cannot vote by marking the Notice and Access Card and returning it. If you would like a paper proxy card, you should follow the instructions in the Notice and Access Card.Notice. The paper proxy card you may receive willwould also provide instructions as to how to authorize via the Internet or telephone your proxy to vote your shares according to your voting instructions. Alternatively, you can mark the paper proxy card you may receive with how you would like your shares voted, sign and date the proxy card, and return it in the envelope provided.

Will a list of record stockholders as of the record date be available?

For the ten days ending the day prior to the Annual Meeting, a list of our record stockholders as of the close of business on the record date will be available for examination by any stockholder of record for a legally valid purpose at our corporate headquarters during regular business hours. To access the list of record stockholders beginning May 12, 20232024 and until the day prior to the Annual Meeting, stockholders should email ir@equilliumbio.com.

Who can vote at the Annual Meeting?

Only stockholders of record at the close of business on March 23, 2023 will be entitled to vote at the Annual Meeting. On this record date, there were 34,414,149 shares of common stock outstanding and entitled to vote.

Stockholder of Record: Shares Registered in Your Name

If, on March 23, 2023, your shares were registered directly in your name with Equillium’s transfer agent, American Stock Transfer & Trust Company, LLC, then you are a stockholder of record. As a stockholder of record, you may vote online during the Annual Meeting or vote by proxy. Whether or not you plan to register and attend the Annual Meeting, we urge you to fill out and return the proxy card that may be delivered to you or vote by proxy over the telephone or on the internet as to ensure your vote is counted.

Beneficial Owner: Shares Registered in the Name of a Broker or Bank

If, on March 23, 2023, your shares were held, not in your name, but rather in an account at a brokerage firm, bank or other similar organization, then you are the beneficial owner of shares held in “street name” and the Notice and Access Card or the proxy materials, if you elected to receive a hard copy, has been forwarded to you by your broker, bank or other nominee who is considered, with respect to those shares, the stockholder of record. As a beneficial owner, you have the right to direct your broker, bank or other agent regarding how to vote the shares in your account. You are also invited to attend the Annual Meeting. However, since you are not the stockholder of record, you may be instructed to obtain a legal proxy from your broker, bank or other nominee and to submit a copy in advance of the meeting in order to vote your shares at the Annual Meeting. Further instructions will be provided to you as part of your registration process.

What am I voting on?

There are fourfive matters scheduled for a vote:

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What if another matter is properly brought before the Annual Meeting?

The Board knows of no other matters that will be presented for consideration at the Annual Meeting. If any other matters are properly brought before the Annual Meeting, it is the intention of the persons named in the proxy card to vote on those matters in accordance with their best judgment.

How do I vote?

YouFor Proposal 1, you may either vote “For” all the nominees to the Board or you may “Withhold” your vote for any nominee to the Board that you specify. With regard to your advisory vote on how frequently we should solicit stockholder advisory approval of executive compensation, you may vote for any one of the following: one year, two years or three years, or you may abstain from voting on that matter. For each of the other matters to be voted on, you may vote “For” or “Against” or abstain from voting.

The procedures for voting are as follows:

Stockholder of Record: Shares Registered in Your Name

If you are a stockholder of record, you may vote at the Annual Meeting or you may vote by proxy over the telephone, vote by proxy through the internet or vote by proxy using thea proxy card that you may be deliveredrequest or that we may elect to you.deliver at a later time. Whether or not you plan to attend the Annual Meeting, we urge you to vote by proxy to ensure your vote is counted. You may still attend the Annual Meeting and vote at the Annual Meetingeven if you have already voted by proxy. This is only required if you want to change your original vote, since votes will not be double counted.

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If I am a stockholder of record and I do not vote, or if I return a proxy card or otherwise vote without giving specific voting instructions, what happens?

If you are a stockholder of record and do not vote by completing your proxy card, by telephone, through the internet or at the Annual Meeting, your shares will not be voted.

If you return a signed and dated proxy card or otherwise vote without marking voting selections, your shares will be voted, as applicable, “For” the election of all three nominees for director, “For” the approval of an amendment to our Amended and Restated Certificate of Incorporation to effect a reverse stock split of our common stock at a ratio in the range of 1-for-2 to 1-for-10, inclusive, “For” the ratification of the selectionappointment by the Audit Committee of the Board of KPMG LLP as theour independent registered public accounting firm of the Company for the fiscal year ending December 31, 20232024, “For” the advisory vote on executive compensation, and “For” “Three Years” as the authorizationpreferred frequency of the adjournment of the Annual Meeting, if necessary,advisory votes to solicit additional proxies if there are not sufficient votes in favor of Proposal 2.approve executive compensation. If any other matter is properly presented at the meeting, your proxyholder (one of the individuals named on your proxy card) will vote your shares using his or her best judgment.

If I am a beneficial owner of shares held in street name and I do not provide my broker or bank with voting instructions, what happens?

If you are a beneficial owner of shares held in street name and you do not instruct your broker, bank or other agent how to vote your shares, your broker, bank or other agent may still be able to vote your shares in its discretion. Under the rules of the New York Stock Exchange (“NYSE”), brokers,Brokers, banks and other securities intermediaries that are subject to NYSE rules may use their discretion to vote your “uninstructed” shares with respect to matters considered to be “routine” under NYSE rules,“routine,” but not with respect to “non-routine”“non-routine” matters. In this regard, ProposalProposals 1, is4 and 5 are considered to be “non-routine” under“non-routine,” NYSE rules meaning that your broker may not vote your shares on this proposalthose proposals in the absence of your voting instructions. However, Proposals 2 and 3 and 4 are each considered to be “routine” matters under NYSE rules“routine,” meaning that if you do not return voting instructions to your broker by its deadline, your shares may be voted by your broker in its discretion on Proposals 2 and 3.

What are “broker non-votes”?

As discussed above, when a beneficial owner of shares held in street name does not give voting instructions to his or her broker, bank or other securities intermediary holding his or her shares as to how to vote on matters deemed to be “non-routine,” the broker, bank or other such agent cannot vote the shares. When there is at least one “routine” matter that the broker, bank or other securities intermediary votes on, the shares that are un-voted on “non-routine” matters are counted as “broker non-votes.” Proposals 2 and 3 are each a “routine” matter and 4.we therefore expect brokers, banks or other securities intermediaries to vote on such proposals. Proposals 1, 4 and 5 are considered “non-routine” and we therefore expect broker non-votes to exist in connection with such proposals.

IfAs a reminder, if you are a beneficial owner of shares held in street name, in order to ensure your shares are voted in the way you would prefer, youmust provide voting instructions to your broker, bank or other agent by the deadline provided in the materials you receive from your broker, bank or other agentagent..

Who is paying for this proxy solicitation?

Equillium will pay for the entire cost of soliciting proxies. In addition to these proxy materials, Equillium’s directors and employees may also solicit proxies in person, by telephone, or by other means of communication. Directors and employees will not be paid any additional compensation for soliciting proxies. We may also reimburse brokerage firms, banks or other agents for the cost of forwarding proxy materials to beneficial owners.

What does it mean if I receive more than one Notice or more than one set of proxy materials?

4If you receive more than one Notice, your shares may be registered in more than one name or in different accounts. Please follow the voting instructions on the Notices to ensure that all of your shares are voted.

Your most recent proxy card or telephone or internet proxy is the one that is counted.

Beneficial Owner: Shares Registered in the Name of Broker or Bank

If your shares are held by your brokerage firm, bank or other agent, you should follow the instructions provided by your broker, bank or other agent.

What vote is required for adoption or approval of each proposal and how will votes be counted?

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When are stockholder proposals and director nominations due for next year’s annual meeting?

To be considered for inclusion in the Company’s proxy materials for next year’s annual meeting of stockholders, your proposal must be submitted in writing by December 13, 2023,12, 2024, to the attention of the Secretary of Equillium, Inc., 2223 Avenida de la Playa, Suite 105, La Jolla, CA 92037. If you wish to submit a proposal (including a director nomination) at the meeting that is not to be included in the Company’s proxy materials for next year’s annual meeting, you must do so between January 23, 202422, 2025 and February 22, 2024.21, 2025. You are also advised to review the Company’s amended and restated bylaws, which contain additional requirements relating to advance notice of stockholder proposals and director nominations. In addition, stockholders who intend to solicit proxies in support of director nominees other than Equillium’s nominees must also comply with the additional requirements of Rule 14a-19(b).

What are “broker non-votes”?Who will count the vote?

When a beneficial ownerA representative of shares held in “street name” does not give instructions toEquillium will tabulate the brokerage firm, bank or other agent holding the sharesvotes and act as to how to vote on matters deemed to be non-routine under applicable rules, the broker or nominee cannot vote the shares. These unvoted shares are counted as “broker non-votes.”

How are votes counted?

Votes will be counted by the inspector of election appointed for the Annual Meeting, who will separately count, for the proposal to elect directors, votes “For,” “Withhold” and broker non-votes; and with respect to the other proposals, votes “For” and “Against,” abstentions and, if applicable, broker non-votes. Abstentions will have no effect on Proposal 1. Abstentions will be counted towards the vote total for Proposals 2, 3 and 4 and will have the same effect as “Against” votes. Broker non-votes will be counted for purposes of determining the presence of a quorum and will have no effect for any proposal other than Proposal 2, for which broker non-votes will have the same effect as “Against” votes.elections.

As a reminder, if you are a beneficial owner of shares held in street name, in order to ensure your shares are voted in the way you would prefer, you must provide voting instructions to your broker, bank or other agent by the deadline provided in the materials you receive from your broker, bank or other agent.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Proxy Statement contains certain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, relating to future events. Such statements are only predictions and involve risks and uncertainties, resulting in the possibility that the actual events or performance will differ materially from such predictions. For a nonexclusive list of major factors which could cause the actual results to differ materially from the predicted results in the forward-looking statements, please refer to the “Risk Factors” in Part I. Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 and in our subsequent periodic reports on Form 10-Q and Form 8-K.

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PROPOSAL 1: ELECTION OF DIRECTORS

The Board is divided into three classes. Each class consists, as nearly as possible, of one-third of the total number of directors, and each class has a three-year term. Vacancies on the Board may be filled only by persons elected by a majority of the remaining directors. A director elected by the Board to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until the director’s successor is duly elected and qualified.

The Board presently has nine members. There are three Class IIIII directors whose term of office expires in 2023: Charles McDermott, Bruce D. Steel2024: Daniel M. Bradbury, Martha J. Demski and Yu (Katherine) Xu, Ph.D.Mark Pruzanski, M.D. Proxies may not be voted for a greater number of persons than the number of nominees named in this proxy statement.Proxy Statement. Mr. McDermott, Mr. SteelBradbury, Ms. Demski and Dr. XuPruzanski are each current directors of the Company. Mr. McDermott and Mr. SteelCompany, were each elected to the Board at the annual meeting of stockholders in 2020,2021 and were each was recommended for reelection to the Board by the Nominating and Corporate Governance Committee of the Board. Dr. Xu was appointed to the Board on February 4, 2021 by the Board to fill a vacancy in the Class II directors created by an increase in the number of directors and was recommended for reelection to the Board by the Nominating and Corporate Governance Committee. If elected at the Annual Meeting, each of these nominees would serve until the 2026 annual meeting2027 Annual Meeting of stockholdersStockholders and until a successor has been duly elected and qualified, or, if sooner, until the director’s death, resignation or removal. It is the Company’s policy to invite directors and nominees for director to attend the Annual Meeting. SevenFive of our then-current directors attended our annual meeting of stockholders in 2022.2023.

Directors are elected by a plurality of the votes of the holders of shares present virtually or represented by proxy and entitled to vote on the election of directors. Accordingly, the three nominees receiving the highest number of affirmative votes will be elected. Shares represented by executed proxies will be voted, if authority to do so is not withheld, for the election of Mr. McDermott, Mr. SteelBradbury, Ms. Demski and Dr. Xu. If any nominee becomes unavailable for election as a result of an unexpected occurrence, shares that wouldPruzanski. We have been voted for that nominee instead will be voted for the election of a substitute nominee proposed by the Company. Each of Mr. McDermott, Mr. Steel and Dr. Xu has agreed to serve if elected. The Company’s management has no reason to believe that any nomineeof the nominees will be unableunavailable or, if elected, will decline to serve. In the event that any of these nominees should become unavailable for election due to any presently unforeseen reason, proxies will be voted for a substitute as designated by the Board, or alternatively, the Board may leave a vacancy on the Board or reduce the size of the Board.

NOMINEESNominees for Election to the Board of Directors

The Nominating and Corporate Governance Committee seeks to assemble a Board that, as a whole, possesses the appropriate balance of professional and industry knowledge, financial expertise and high-level management experience necessary to oversee and direct the Company’s business. To that end, the Nominating and Corporate Governance Committee has identified and evaluated the nominees in the broader context of the Board’s overall composition, with the goal of recruiting members who complement and strengthen the skills of other members and who also exhibit integrity, collegiality, sound business judgment and other qualities that the Nominating and Corporate Governance Committee views as critical to effective functioning of the Board. To provide a mix of experience and perspective on the Board, the Nominating and Corporate Governance Committee also takes into account geographic, gender, age, racial and ethnic diversity.

The brief biographies of each of our nominees for election to the Board as Class III directors, and all other directors are set forth below, include information, asincluding the offices held, other business directorships and the class and term of each director nominee and director. Each of the date of this Proxy Statement, regarding thebiographies highlights specific and particular experience, qualifications, attributes, orand skills of eachthat led us to conclude that such person should serve as a director. We believe that, as a whole, our Board possesses the requisite skills and characteristics, leadership traits, work ethic, and independence to provide effective oversight. No director or nominee that ledexecutive officer is related by blood, marriage, or adoption to any other director or executive officer. Except as described below, no arrangements or understandings exist between any director and any other person pursuant to which such person was selected as a director or nominee.

In February 2021, we entered into a securities purchase agreement (the “Purchase Agreement”) with two institutional investors managed by Decheng Capital, whereby we sold 4,285,710 shares of common stock and issued warrants to purchase 1,285,713 shares of common stock for gross proceeds of $30.0 million. Pursuant to the Nominating and Corporate Governance Committee to believe that that nominee should continue to serve on the Board. However, eachterms of the members of the Nominating and Corporate Governance Committee may have a variety of reasons why he or she believes a particular person would be an appropriate nominee for the Board, and these views may differ from the views of other members.

Nominees for Election for a Three-year Term Expiring at the 2026 Annual Meeting

Charles McDermott, 51, has served as a member of our Board since September 2018. Mr. McDermott has served as Chairman, President and Chief Executive Officer of Primmune Therapeutics, Inc., a privately-held biotechnology company, since March 2019. From September 2017 to May 2018, Mr. McDermott served as President and Chief Business Officer of Impact Biomedicines, Inc., a privately-held biotechnology company. Prior to that, Mr. McDermott served as President and Chief Business Officer of Kala Pharmaceuticals, Inc., a publicly-held biopharmaceutical company, from June 2015 to August 2017. Previously, he served as Interim President and Chief

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THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” EACH NAMED NOMINEE.

Directors Continuing in Office Until the 2024 Annual Meeting

Daniel M. Bradbury, 61, has served as the Executive Chairman of our Board since January 2020 and has been a member and the chairman of our Board since March 2017. He served as our Chief Executive Officer from June 2018 through December 2019. Mr. Bradbury is a co-founder of Equillium and served as our President from March 2017 until June 2018. Mr. Bradbury is the founder and has served as the managing member of BioBrit, LLC (“BioBrit”), a

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Director and Senior Director of Clinical Development between March 2006 and January 2010. Dr. Troupin received her Doctorate in Medicine from the University of Pennsylvania School of Medicine where she also completed her M.B.A. from the Wharton School of Business, with an emphasis in health care management. She holds a B.A. in Biochemistry and Cell Biology from the University of California San Diego.

		President of Clinical Development between October 2016 and March 2017. From September 2014 to June 2016, Dr. Troupin was Senior Vice President, Chief Medical Officer at Apricus Biosciences, Inc, a publicly-held biopharmaceutical company. Prior to joining Apricus Biosciences, Inc., Dr. Troupin held positions of increasing responsibility with Vivus Inc., a publicly-held pharmaceutical company, as Vice President Medical Affairs between February 2012 and August 2014, as Senior Director Medical Affairs between January 2010 and January 2012 and as Director and Senior Director of Clinical Development between March 2006 and January 2010. Dr. Troupin received her Doctorate in Medicine from the University of Pennsylvania School of Medicine where she also completed her M.B.A. from the Wharton School of Business, with an emphasis in health care management. She holds a B.A. in Biochemistry and Cell Biology from the University of California San Diego.
		Skills and Qualifications
		Our Nominating and Corporate Governance Committee and Board believe that Dr. Troupin is qualified to serve on our Board due to her extensive experience leading clinical and medical affairs functions.

Directors Continuing in Office Until the 2026 Annual Meeting of Stockholders

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INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE

INDEPENDENCE OF THE BOARD OF DIRECTORSIndependence of the Board of Directors

As required under the Nasdaq Stock Market listing standards, a majority of the members of a listed company’s board of directors must qualify as “independent,” as affirmatively determined by the board of directors. Our Board consults with our counsel to ensure that the Board’s determinations are consistent with relevant securities and other laws and regulations regarding the definition of “independent,” including those set forth in pertinent listing standards of Nasdaq, as in effect from time to time.

Consistent with these considerations, after review of all relevant identified transactions or relationships between each director, or any of such director’s family members, and us, our senior management and our independent auditors, the Board has affirmatively determined that the following six directors are independent directors as defined by Rule 5605(a)(2) of the Nasdaq Listing Rules: Ms. Demski, Dr. Manian, Mr. McDermott, Dr. Pruzanski, Dr. Troupin and Dr. Xu. In making this determination, the Board found that none of these directors had a material or other disqualifying relationship with us. Mr. Bradbury, Dr. Connelly and Mr. Steel are not considered independent because of their current employment with us.

BOARD LEADERSHIP STRUCTUREBoard Leadership Structure

Our Board is currently chaired by our Executive Chairman, Mr. Bradbury. In January 2020, Mr. Bradbury transitioned from his prior role of Chief Executive Officer to Executive Chairman of our Board of Directors. With Mr. Bradbury’s extensive history with and knowledge of our company, we believe his role as our Executive Chairman facilitates a regular flow of information between the Board and management and ensures that they both act with a common purpose. Our Board does not have a lead independent director.

ROLE OF THE BOARD IN RISK OVERSIGHTRole of the Board in Risk Oversight

One of the key functions of our Board is informed oversight of our risk management process. Our Board does not have a standing risk management committee, but rather administers this oversight function directly through the Board as a whole, as well as through various standing committees of our Board that address risks inherent in their respective areas of oversight. In particular, our Board is responsible for monitoring and assessing strategic risk exposure, including a determination of the nature and level of risk appropriate for us. Our Audit Committee has the responsibility to consider and discuss our major financial risk exposures and the steps our management has taken to monitor and control these exposures, including guidelines and policies to govern the process by which risk assessment and management is undertaken. Our Nominating and Corporate Governance Committee monitors the effectiveness of our corporate governance guidelines, including whether they are successful in preventing illegal or improper liability-creating conduct. Our Compensation Committee assesses and monitors whether any of our compensation policies and programs has the potential to encourage excessive risk-taking.

MEETINGS OF THE BOARD OF DIRECTORSMeetings of the Board of Directors

The Board met 14six times and acted by unanimous written consent threefour times during 2022.2023. All directors attended at least 75% of the aggregate number of meetings of the Board and of the committees on which they served during 2022.2023.

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Executive Sessions

Executive sessions, which are meetings at which only independent directors are present, are regularly scheduled throughout the year, typically at the end of each regular Board meeting and at the end of each committee meeting and as frequently as such independent directors deem appropriate. A director designated at each executive session by the non-management or independent directors, as applicable, presides at the executive sessions.

INFORMATION REGARDING COMMITTEES OF THE BOARD OF DIRECTORS

The Board has an Audit Committee, a Compensation Committee and a Nominating and Corporate Governance Committee. The following table provides current membership and meeting information for fiscal year 20222023 for each of these committees of the Board:

Below is a description of each committee of the Board.

Each of the committees has authority to engage legal counsel or other experts or consultants, as it deems appropriate to carry out its responsibilities. The Board has determined that each member of each committee meets the applicable Nasdaq rules and regulations regarding “independence” and that each member is free of any relationship that would impair his or her individual exercise of independent judgment with regard to us.

Audit Committee

The Audit Committee of the Board was established by the Board in accordance with Section 3(a)(58)(A) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), to oversee our corporate accounting and financial reporting processes and audits of its financial statements. For this purpose, the Audit Committee performs several functions, including, among other things:

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The Audit Committee is composed of three directors: Ms. Demski (chair), Dr. Manian and Dr. Xu. The Audit Committee met eight times during the 20222023 fiscal year. The Board has adopted a written Audit Committee charter that is available to stockholders on our website at www.equilliumbio.com. The information on our website is not incorporated by reference into this Proxy Statement or our Annual Report on Form 10-K for the fiscal year ended December 31, 2022.2023.

The Board reviews the Nasdaq listing standards definition of independence for Audit Committee members on an annual basis and has determined that all members of our Audit Committee are independent (as independence is currently defined in Rule 5605(c)(2)(A)(i) and (ii) of the Nasdaq listing standards and Rule 10A-3 of the Exchange Act).

The Board has also determined that Ms. Demski qualifies as an “audit committee financial expert,” as defined in applicable SEC rules. The Board made a qualitative assessment of Ms. Demski’s level of knowledge and experience based on a number of factors, including her formal education, prior experience, business acumen and independence.

Report of the Audit Committee of the Board of Directors*

The Audit Committee has reviewed and discussed the audited consolidated financial statements for the fiscal year ended December 31, 2022 with our management. The Audit Committee has discussed with the independent registered public accounting firm the matters required to be discussed under the applicable requirements of the Public Company Accounting Oversight Board (“PCAOB”) and the Securities and Exchange Commission. The Audit Committee has also received the written disclosures and the letter from the independent registered public accounting firm required by applicable requirements of the PCAOB regarding the independent registered public accounting firm’s communications with the Audit Committee concerning independence, and has discussed with the independent registered public accounting firm the accounting firm’s independence. Based on the foregoing, the Audit Committee has recommended to the Board that the audited consolidated financial statements be included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022.

Compensation Committee

The Compensation Committee of the Board is composed of three directors: Dr. Manian (chair), Ms. Demski and Dr. Pruzanski. Our Board has determined that each of the members of our Compensation Committee is a non-employee director, as defined in Rule 16b-3 promulgated under the Exchange Act and satisfies the Nasdaq independence requirements. The Compensation Committee met five times during the 20222023 fiscal year. The Board has adopted a written Compensation Committee charter that is available to stockholders on our website at www.equilliumbio.com. The information on our website is not incorporated by reference into this Proxy Statement or our Annual Report on Form 10-K for the fiscal year ended December 31, 2022.2023.

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Compensation Committee Processes and Procedures

Typically, the Compensation Committee meets at least three times per year (but in no event less than annually) and with greater frequency, if necessary. The agenda for each meeting is usually developed by the chair of the Compensation Committee, in consultation with management. The Compensation Committee meets regularly in executive session. However, from time to time, various members of management and other employees as well as outside advisors or consultants may be invited by the Compensation Committee to make presentations, to provide financial or other background information or advice or to otherwise participate in Compensation Committee

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Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee of the Board is responsible for identifying, reviewing and evaluating candidates to serve as our directors (consistent with criteria approved by the Board), reviewing and evaluating incumbent directors, selecting or recommending to the Board for selection candidates for election to the Board, making recommendations to the Board regarding the membership of the committees of the Board, assessing the performance of the Board, and developing a set of corporate governance principles for us.

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the Nominating and Corporate Governance Committee at the following address: c/o Equillium, Inc., 2223 Avenida de la Playa, Suite 105, La Jolla, California 92037, Attn: Secretary, no later than the close of business on the 90^th90th day nor earlier than the close of business on the 120^th120th day prior to the first anniversary of the preceding year’s annual meeting. Submissions must include the name and address of our stockholder on whose behalf the submission is made; the number of Company shares that are owned beneficially by such stockholder as of the date of the submission; the full name of the proposed candidate; a description of the proposed candidate’s business experience for at least the previous five years; complete biographical information for the proposed candidate; and a description of the proposed candidate’s qualifications as a director. Any such submission must be accompanied by the written consent of the proposed nominee to be named as a nominee and to serve as a director if elected.

Board Diversity

Our Board monitors the mix of skills and experience of its directors to help ensure it has the necessary tools to perform its oversight function effectively. The Board fully appreciates the value of a diversity of viewpoints, background and experiences as important to the selection of directors to enhance the Board’s cognitive diversity and quality of dialogue in the Boardroom.

We believe that our current directors possess diverse professional experiences, skills and backgrounds, in addition to, among other characteristics, high standards of personal and professional ethics and valuable knowledge of our business and our industry.

Below is our Nasdaq Board Diversity Matrix for fiscal year 2024 and last year’s Board Diversity Matrix is available in our 2023 proxy statement filed with the SEC on April 11, 2023. The following Board Diversity Matrix sets forth certain self-identified personal demographic characteristics of our directors.

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Board’s Oversight of Strategy

Our Board is deeply engaged and involved in overseeing our long-range strategy, including evaluating key market opportunities and trends, the company’s strengths, weaknesses, opportunities and threats, external changes affecting the company and industry and competitive developments. This also includes aspects of our environmental, social and governance (“ESG”) initiatives that relate to our strategy. Our Board’s oversight of risk is another integral component of the Board’s oversight and engagement on strategic matters. Strategy-related matters are regularly discussed at Board meetings and, when relevant, at Committee meetings. Matters of strategy also inform committee-level discussions of many issues, including enterprise risk. Engagement of the Board on these issues and other matters of strategic importance continues in between meetings, including through updates to the Board on significant items and discussions between the Chief Executive Officer and our Executive Chairman on a periodic basis. Each director is expected to and does bring to bear their own talents, insights, and experiences to these strategy discussions.

Cybersecurity and Data Privacy Oversight

Our Board addresses the company’s cybersecurity risk management as part of its general oversight function. The Audit Committee is responsible for reviewing the company’s guidelines and policies with respect to risk assessment and risk management, including those related to assessment and mitigation of risks from cybersecurity threats.

Our cybersecurity risk assessment and management processes are implemented and maintained by certain company management, including our Head of IT, who holds a Microsoft Certification, and our Chief Operating Officer, who earned a Cybersecurity for Directors certificate from the Corporate Governance Institute.

Management is also responsible for hiring appropriate personnel, helping to integrate cybersecurity risk considerations into the company’s overall risk management strategy, and communicating key priorities to relevant personnel. The Head of IT and Chief Operating Officer are responsible for helping prepare the company for cybersecurity incidents, approving cybersecurity processes, and reviewing security assessments and other security-related reports.

Our cybersecurity incident response processes are designed to escalate certain cybersecurity incidents to members of management depending on the circumstances and designated risk level, including the Chief Financial Officer, Chief Executive Officer and/or full Executive Leadership Team, who participates in our disclosure controls and procedures. The Head of IT and Chief Operating Officer work with the company’s incident response team to help the company mitigate and remediate cybersecurity incidents of which they are notified. Notifications may be received via automated alerts and reports from electronic system monitoring tools that we have implemented to assist in the protection against phishing, malware, business email compromise, ransomware, and other cyberthreats, or may be submitted directly to our Head of IT from employees who believe they may have received a suspicious threat. In addition, the company’s incident response processes include reporting to the Audit Committee for certain cybersecurity incidents.

The Audit Committee receives periodic reports from the Head of IT and Chief Operating Officer concerning the company’s significant cybersecurity threats and risk and the processes the company has implemented to address them. The Audit Committee also receives summaries or presentations related to the company’s information systems and data and cybersecurity threats, risk and mitigation.

Stockholder Communications with The Board of Directors

The Board has adopted a formal process by which stockholders may communicate with the Board or any of its directors. Stockholders who wish to communicate with the Board may do so by sending written communications addressed to the Secretary of Equillium, Inc., 2223 Avenida de la Playa, Suite 105, La Jolla, California 92037. These communications will be reviewed by the Secretary of Equillium who will determine whether the communication is appropriate for presentation to the Board or the relevant director. The purpose of this screening is to allow the Board to avoid having to consider irrelevant or inappropriate communications (such as advertisements, solicitations and hostile communications).

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PROPOSAL 2

2: APPROVAL OF AN AMENDMENT TO OUR AMENDED AND

RESTATED CERTIFICATE OF

INCORPORATION TO EFFECT A REVERSE STOCK

SPLIT OF OUR COMMON STOCK

Background

Our Board of Directors has unanimously approved a series of alternate amendments to our Amended and Restated Certificate of Incorporation, which would:

Accordingly, effecting a Reverse Stock Split would reduce the number of outstanding shares of our common stock. The effectiveness of any one of these amendments and the abandonment of the other amendments, or the abandonment of all of these amendments, will be determined by our Board of Directors following the Annual Meeting and prior to the one-year anniversary of the Annual Meeting, or May 22, 2024.December 31, 2025. Our Board of Directors has recommended that these proposed amendments be presented to our stockholders for approval.

Our stockholders are being asked to approve these proposed amendments pursuant to Proposal 2, and to grant authorization to our Board of Directors to determine, at its option, whether to implement a Reverse Stock Split, including its specific timing and ratio.

Should we receive the required stockholder approvals for Proposal 2, our Board of Directors will have the sole authority to elect, at any time on or prior to the one-year anniversary of the Annual MeetingDecember 31, 2025 and without the need for any further action on the part of our stockholders, whether to effect a Reverse Stock Split and the number of whole shares of our common stock, between and including two (2) and ten (10), that will be combined into one share of our common stock.

Notwithstanding approval of Proposal 2 by our stockholders, our Board of Directors may, at its sole option, abandon the proposed amendments and determine prior to the effectiveness of any filing with the Secretary of State of the State of Delaware not to effect any Reverse Stock Split, as permitted under Section 242(c) of the General Corporation Law of the State of Delaware. If our Board of Directors does not implement a Reverse Stock Split on or prior to the one-year anniversary of the Annual Meeting,December 31, 2025, stockholder approval would again be required prior to implementing any Reverse Stock Split.

By approving Proposal 2, our stockholders will: (a) approve a series of alternate amendments to our Amended and Restated Certificate of Incorporation pursuant to which any whole number of outstanding shares of common stock between and including two (2) and ten (10) could be combined into one share of common stock; and (b) authorize our Board of Directors to file only one such amendment, as determined by the Board at its sole option, and to abandon each amendment not selected by the Board. Our Board of Directors may also elect not to undertake any Reverse Stock Split and therefore abandon all amendments.

Approval of Reverse Stock Split of our Common Stock (Proposal 2)

Our Board of Directors has adopted and is recommending that our stockholders approve a series of alternate amendments to our Amended and Restated Certificate of Incorporation to effect a Reverse Stock Split. The text of the proposed form of Certificate of Amendment to our Amended and Restated Certificate of Incorporation, which we refer to as the Certificate of Amendment, is attached hereto as Appendix A.

We are proposing that our Board of Directors have the discretion to select the Reverse Stock Split ratio from within a range between and including 1-for-2 and 1-for-10, rather than proposing that stockholders approve a specific ratio at this time, in order to give our Board of Directors the flexibility to implement a Reverse Stock Split at a ratio that reflects the Board’s then-current assessment of the factors described below under “Criteria to be Used

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The Board of Directors has considered the potential harm to us and our stockholders should Nasdaq delist our common stock from The Nasdaq Global Market or, in the event we transfer to The Nasdaq Capital Market, The Nasdaq Capital Market. Delisting could adversely affect the liquidity of our common stock since alternatives, such as the OTC Bulletin Board and the pink sheets, are generally considered to be less efficient markets. An investor likely would find it less convenient to sell, or to obtain accurate quotations in seeking to buy, our common stock on an over-the-counter market. Many investors likely would not buy or sell our common stock due to difficulty in accessing over-the-counter markets, policies preventing them from trading in securities not listed on a national exchange or for other reasons. In addition, our failure to cause our shares of common stock to remain listed on a nationally recognized stock exchange in the United States having listing standards at least as restrictive as The Nasdaq Capital Market would constitute an event of default under our Loan and Security Agreement with Oxford Finance, LLC and Silicon Valley Bank.

The Board of Directors believes that the proposed Reverse Stock Split is a potentially effective means for us to, if applicable, regain and maintain compliance with the $1.00 minimum bid price requirement and to avoid, or at least mitigate, the likely adverse consequences of our common stock being delisted from The Nasdaq Global Market and/or The Nasdaq Capital Market by producing the immediate effect of increasing the bid price of our common stock.

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percentage decline as an absolute number and as a percentage of our overall market capitalization may be greater than would occur in the absence of the Reverse Stock Split. Even if the market price per post-Reverse Stock Split share of our common stock remains in excess of $1.00 per share, we may be delisted due to a failure to meet other continued listing requirements, including Nasdaq requirements related to the minimum number of shares that must be in the public float, the minimum market value of the public float and the minimum number of “round lot” holders.

The proposed Reverse Stock Split may decrease the liquidity of our common stock and result in higher transaction costs. The liquidity of our common stock may be negatively impacted by a Reverse Stock Split, given the reduced number of shares that would be outstanding after the Reverse Stock Split, particularly if the stock price does not increase as a result of the Reverse Stock Split. In addition, if a Reverse Stock Split is implemented, it will increase the number of our stockholders who own “odd lots” of fewer than 100 shares of common stock. Brokerage commission and other costs of transactions in odd lots are generally higher than the costs of transactions of more than 100 shares of common stock. Accordingly, a Reverse Stock Split may not achieve the desired results of increasing marketability and liquidity of our common stock described above.

The effective increase in the authorized number of shares of our common stock as a result of the Reverse Stock Split could have anti-takeover implications. The implementation of a Reverse Stock Split will result in an effective increase in the authorized number of shares of our common stock, which could, under certain circumstances, have anti-takeover implications. The additional shares of common stock that would become available for issuance if this Proposal 2 is approved and a Reverse Stock Split is implemented could be used by us to oppose a hostile takeover attempt or to delay or prevent changes in control or our management. For example, without further stockholder approval, the Board could adopt a “poison pill” which would, under certain circumstances related to an acquisition of our securities that is not approved by the Board, give certain holders the right to acquire additional shares of our common stock at a low price. The Board also could strategically sell shares of common stock in a private transaction to purchasers who would oppose a takeover or favor the current Board. Although this Proposal 2 has been prompted by business and financial considerations and not by the threat of any hostile takeover attempt (nor is the Board currently aware of any such attempts directed at us), stockholders should be aware that approval of this Proposal 2 could facilitate future efforts by us to deter or prevent changes in control, including transactions in which the stockholders might otherwise receive a premium for their shares over then current market prices.

Effects of Reverse Stock Split

After the effective date of any Reverse Stock Split that our Board of Directors elects to implement, each stockholder will own a reduced number of shares of common stock. However, any Reverse Stock Split will affect all of our stockholders uniformly and will not affect any stockholder’s percentage ownership interests in Equillium, except to the extent that the Reverse Stock Split results in any of our stockholders owning a fractional share as described below. Voting rights and other rights and preferences of the holders of our common stock will not be affected by a Reverse Stock Split (other than as a result of the payment of cash in lieu of fractional shares). For example, a holder of 2% of the voting power of the outstanding shares of our common stock immediately prior to a Reverse Stock Split would continue to hold 2% (assuming there is no impact as a result of the payment of cash in lieu of issuing fractional shares) of the voting power of the outstanding shares of our common stock immediately after such Reverse Stock Split. The number of stockholders of record will not be affected by a Reverse Stock Split (except to the extent that any stockholder holds only a fractional share interest and receives cash for such interest after such Reverse Stock Split).

The principal effects of a Reverse Stock Split will be that:

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The following table contains approximate information, based on share information as of March 23, 2023,April 1, 2024, relating to our outstanding common stock based on the proposed Reverse Stock Split ratios (without giving effect to the treatment of fractional shares):

After the effective date of any Reverse Stock Split that our Board of Directors elects to implement, our common stock would have a new committee on uniform securities identification procedures (CUSIP) number, a number used to identify our common stock.

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Record and Beneficial Stockholders

If this Proposal 2 is approved by our stockholders and our Board of Directors elects to implement a Reverse Stock Split, stockholders of record holding all of their shares of our common stock electronically in book-entry form under the direct registration system for securities will be automatically exchanged by the exchange agent and will receive a transaction statement at their address of record indicating the number of new post-split shares of our common stock they hold after the Reverse Stock Split along with payment in lieu of any fractional shares. Non-registered stockholders holding common stock through a bank, broker or other nominee should note that such banks, brokers or other nominees may have different procedures for processing the Reverse Stock Split and making payment for fractional shares than those that would be put in place by us for registered stockholders. If you hold your shares with such a bank, broker or other nominee and if you have questions in this regard, you are encouraged to contact your nominee.

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Accordingly, each stockholder should consult with such stockholder’s own tax advisor with respect to all of the potential tax consequences to such stockholder of the Reverse Stock Split.

For purposes of this discussion, a “U.S. Holder” means a beneficial owner of shares of our common stock that is any of the following:

If a partnership (including any entity or arrangement treated as a partnership for U.S. federal income tax purposes) holds shares of our common stock, the tax treatment of a partner in the partnership generally will depend upon the status of the partner and the activities of the partnership. Partnerships holding our common stock and the partners therein should consult their tax advisors regarding the tax consequences to them of the Reverse Stock Split.

EACH STOCKHOLDER SHOULD CONSULT ITS TAX ADVISORS WITH RESPECT TO THE PARTICULAR TAX CONSEQUENCES OF THE REVERSE STOCK SPLIT TO SUCH STOCKHOLDER.

Taxation of U.S. Holders

The Reverse Stock Split should constitute a “recapitalization” for U.S. federal income tax purposes. As a recapitalization, except as described below with respect to cash received in lieu of fractional shares, a U.S. Holder should not recognize gain or loss as a result of the Reverse Stock Split. A U.S. Holder’s aggregate tax basis in the shares of the common stock received pursuant to the Reverse Stock Split should equal the U.S. Holder’s aggregate tax basis in the shares of the common stock surrendered, and such U.S. Holder’s holding period in the shares of the common stock received should include the holding period of the shares of the common stock surrendered. Treasury regulations promulgated under the Code provide detailed rules for allocating the tax basis and holding period of shares of common stock surrendered pursuant to the Reverse Stock Split to shares of common stock received pursuant to the Reverse Stock Split. U.S. Holders holding shares of common stock that were acquired on different dates and at different prices should consult their tax advisors regarding the allocation of the tax basis and holding period of such shares.

A U.S. Holder who receives cash in lieu of a fractional share of common stock pursuant to the Reverse Stock Split generally should recognize capital gain or loss in an amount equal to the difference, if any, between the amount of cash received and the portion of the U.S. Holder’s tax basis in the shares of common stock surrendered that is allocated to such fractional share of common stock. Such capital gain or loss generally should be long-term capital gain or loss if the U.S. Holder’s holding period for the common stock surrendered in the Reverse Stock Split exceeds one year at the time of the Reverse Stock Split. Long-term capital gains of non-corporate U.S. Holders are generally subject to preferential tax rates. There are limitations on the deductibility of capital losses under the Code.

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PROPOSAL 3

3: RATIFICATION OF SELECTIONAPPOINTMENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Audit Committee has selectedappointed KPMG LLP (“KPMG”) as the Company’sour independent registered public accounting firm for the fiscal year ending December 31, 20232024 and has further directed that management submit the selection of its independent registered public accounting firm for ratification by the stockholders at the Annual Meeting.Meeting and recommended that stockholders ratify such selection. KPMG has audited the Company’sour financial statements since 2018. Representatives of KPMG are expected to be present at the Annual Meeting. They will have an opportunity to make a statement if they so desire and will be available to respond to appropriate questions.

Neither the Company’sour amended and restated bylaws nor other governing documents or law require stockholder ratification of the selectionappointment of KPMG as the Company’sour independent registered public accounting firm. However, the Audit Committee is submitting the selection of KPMG to the stockholders for ratification as a matter of good corporate practice. If the stockholders fail to ratify the selection,appointment, the Audit Committee will reconsider whether or not to retain that firm. Even if the selection is ratified, the Audit Committee in its discretion may direct the appointment of different independent auditors at any time during the year if they determine that such a change would be in the best interests of the Companyus and itsour stockholders.

The affirmative vote of the holders of a majority of the shares present virtually or represented by proxy and entitled to vote on the matter at the Annual Meeting will be required to ratify the selectionappointment of KPMG.

PRINCIPAL ACCOUNTANT FEES AND SERVICESPrincipal Accountant Fees and Services

The following table represents aggregate fees billed to us by KPMG for the fiscal years ended December 31, 20222023 and 2021:2022:

All fees described above were pre-approved by the Audit Committee.

In connection with the audit of our 20222023 financial statements, we entered into an engagement agreement with KPMG that sets forth the terms by which KPMG will perform audit services for us.

PRE-APPROVAL POLICIESPre-Approval AND PROCEDURESPolicies and Procedures

The Audit Committee must pre-approve the the audit and non-audit services rendered by our independent registered public accounting firm.

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Report of the Audit Committee of the Board of Directors*

The Audit Committee has reviewed and discussed the audited consolidated financial statements for the fiscal year ended December 31, 2023 with our management. The Audit Committee has discussed with the independent registered public accounting firm the matters required to be discussed under the applicable requirements of the Public Company Accounting Oversight Board (“PCAOB”) and the Securities and Exchange Commission. The Audit Committee has also received the written disclosures and the letter from the independent registered public accounting firm required by applicable requirements of the PCAOB regarding the independent registered public accounting firm’s communications with the Audit Committee concerning independence, and has discussed with the independent registered public accounting firm the accounting firm’s independence. Based on the foregoing, the Audit Committee has recommended to the Board that the audited consolidated financial statements be included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023.

THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” PROPOSAL 3.

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PROPOSAL 44: ADVISORY VOTE ON EXECUTIVE COMPENSATION

AUTHORIZATION OF AN ADJOURNMENT OF THE ANNUAL MEETING, IF NECESSARY,In accordance with the requirements of Section 14A of the Exchange Act and the related rules of the SEC, our stockholders are being asked to approve, in an advisory, non-binding vote, the compensation of our named executive officers as disclosed pursuant to Item 402 of Regulation S-K, including the compensation tables and narrative discussion. In considering their vote, we urge stockholders to review the information on our compensation policies and decisions regarding the named executive officers presented in the Executive and Director Compensation section beginning on page 46.

TO SOLICIT ADDITIONAL PROXIES

General

This advisory resolution, commonly referred to as a “say-on-pay” resolution, is non-binding. Although this resolution is non-binding, the Board and the Compensation Committee value the opinions of our stockholders and will review and consider the voting results when making future compensation decisions for our named executive officers. If the “Three Year” option is the option that receives the highest number of affirmative votes as to the frequency of future say-on-pay votes under Proposal 5, we expect that we will conduct our next say-on-pay vote at the 2027 Annual Meeting of Stockholders.

We believe that our compensation components provide a reasonable balance of base compensation and long-term equity-based incentive compensation that is convenedclosely aligned with our overall performance. We aim to provide executive officers with a reasonable level of security through base salary and a quorumbenefits, while rewarding them through cash and equity-based incentive compensation to achieve business objectives and create stockholder value. We believe that each of our compensation components is present, but thereintegral to attracting, retaining, and rewarding qualified named executive officers.

The text of the resolution in respect of Proposal 4 is as follows:

“RESOLVED, that the compensation paid to the Company’s named executive officers as disclosed pursuant to Item 402 of Regulation S-K, including the compensation tables and narrative discussion, is hereby approved.”

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PROPOSAL 5: ADVISORY VOTE ON THE FREQUENCY OF SOLICITATION OF ADVISORY STOCKHOLDER APPROVAL OF EXECUTIVE COMPENSATION

In accordance with the requirements of Section 14A of the Exchange Act and the related rules of the SEC, our stockholders are also entitled to vote, on an advisory basis, on whether the “say-on-pay” vote, as required by Section 14A of the Exchange Act, should occur every one, two, or three years. The vote on the frequency of the say-on-pay vote, just as with the say-on-pay vote itself, is advisory only, and it also is not sufficientbinding on us or on our Board of Directors. Although the vote is non-binding, the Compensation Committee and the Board will carefully consider the outcome of the vote when determining the frequency of future stockholder advisory votes to approve Proposal 2, or if therethe compensation of our named executive officers.

Although our executive compensation programs are insufficient votesdesigned to constitutepromote a quorum,long-term connection between pay and performance, after careful consideration, the Board has determined that a say-on-pay vote that occurs every three years is the most appropriate alternative for our proxy holders may movecompany at this time. As a biotechnology company, we have important milestones relating to adjourn the Annual Meeting atdrug development that time in order to enabledo not occur every calendar year. While executive compensation is evaluated annually, the Board of Directors to solicit additional proxies.

In this proposal, we are askingalso considers progress over a multi-year timeframe, which is common in small- and mid-capitalization companies in our stockholders to authorize the holder of any proxy solicited by theindustry. The Board of Directors believes that a vote every three years provides stockholders the opportunity to vote in favor of adjourning the Annual Meeting to another time and place, if necessary or appropriate (as determined in good faith byevaluate our compensation program on a more thorough, longer-term basis than an annual vote. Therefore, the Board recommends that you vote for a “Three Year” frequency for the say-on-pay vote.

Although the Board recommends a say-on-pay vote be held three years, you may vote one of Directors)four choices for this Proposal 5 on the proxy card: “One Year”, to solicit additional proxies in the event there are not sufficient votes to approve Proposal 2. If our stockholders approve this proposal, we could adjourn the Annual Meeting and any adjourned“Two Years”, “Three Years”, or postponed session“Abstain.” The text of the Annual Meeting and useresolution in respect of Proposal 5 is as follows:

“RESOLVED, that the additional time to solicit additional proxies, includingoption of once every one year, two years, or three years that receives the solicitation of proxies from our stockholders that have previously voted. Among other things, approval of this proposal could mean that, even if we had received proxies representing a sufficienthighest number of votes to defeat Proposal 2, we could adjourn the Annual Meeting without a vote on such proposal and seek to convince our stockholders to change their votes in favor of such proposal.

If it is necessary or appropriate (as determined in good faith by the Board of Directors) to adjourn the Annual Meeting, no notice of the adjourned meeting is required to be given to our stockholders, other than an announcement at the Annual Meeting of the time and place to which the Annual Meeting is adjourned, so long as the meeting is adjourned for 30 days or less and no new record date is fixed for the adjourned meeting. At the adjourned meeting, we may transact any business which might have been transacted at the original meeting.

Vote Required

Approval of this proposal requires the affirmative vote of a majorityvotes of the shares present virtually or represented by proxy at the Annual Meeting. Abstentionsmeeting and entitled to vote generally on the subject matter for this resolution will havebe determined to be the same effectpreferred frequency with which the Company is to hold an advisory stockholder vote to approve the compensation paid to the Company’s named executive officers, as an “against” vote on this proposal.disclosed pursuant to Item 402 of Regulation Broker non-votes, ifS-K, any, will have no effect.

THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” PROPOSAL 4including the compensation tables and narrative discussion.”

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EXECUTIVE OFFICERS

Daniel M. Bradbury, 61,62, has served as our Executive Chairman of our Board since January 2020 and has been a member and the chairman of our Board since March 2017. For additional information regarding Mr. Bradbury’s industry experience and education, see above under “Directors Continuing in Office Until“Class III Director Nominees for Election at the 2024 Annual Meeting.”

Bruce D. Steel, 56,57, has served as our President and as our Chief Executive Officer since January 2020 and as a member of our Board since March 2017. Mr. Steel served as our President and Chief Business Officer from June 2018 through December 2019. For additional information regarding Mr. Steel’s industry experience and education, see above under “Nominees for Election for a Three-year Term Expiring at“Directors Continuing in Office Until the 2026 Annual Meeting.”

Stephen Connelly, Ph.D., 41,42, has served as our Chief Scientific Officer since January 2018 and as a member of our Board since March 2017. For additional information regarding Dr. Connelly’s industry experience and education, see above under “Directors Continuing in Office Until the 2025 Annual Meeting.”

Jason A. Keyes, 52,53, has served as our Chief Financial Officer since March 2018 and also has served as a director of our Australian subsidiary since January 2019. Mr. Keyes formerly served on the board of directors, including as chair of the audit committee, of Sesen Bio, Inc., a publicly-held biopharmaceutical company, from 2020 to 2023. From January 2013 to February 2018, Mr. Keyes held positions of increasing responsibility at Orexigen Therapeutics, Inc., a publicly-held pharmaceutical company which filed a voluntary petition for Chapter 11 bankruptcy in March 2018, most recently as Executive Vice President and Chief Financial Officer. Mr. Keyes held positions of increasing responsibility at Amylin Pharmaceuticals, Inc., a publicly-held biopharmaceutical company, from August 2007 until January 2013, most recently as Senior Director of Finance. Prior to joining Amylin, Mr. Keyes held positions of increasing responsibility in finance and corporate strategy at Amgen Inc., a publicly-held biopharmaceutical company, and Baxter Healthcare Corporation, a publicly-held healthcare company. Mr. Keyes formerly served on the board of directors of Sesen Bio, Inc., a publicly-held biopharmaceutical company, from 2020 to 2023. Mr. Keyes received his B.S. and M.S. degrees in Civil Engineering from Stanford University and an M.B.A. from the Anderson School at the University of California, Los Angeles.

Joel Rothman, 54, has served as our Chief Development Officer since January 2021 and also has served as a director of our Australian subsidiary since December 2020. He served as our Senior Vice President, Development Operations between December 2019 and December 2020 and as our Vice President, Development Operations between September 2018 and December 2019. Prior to joining Equillium, Mr. Rothman led development operations in the Vice President role for several other leading pharmaceutical and biotechnology companies including at Cytokinetics, Inc. from January 2017 to September 2018, at Raptor Pharmaceuticals, Inc. (acquired by Horizon Therapeutics plc) from June 2015 to January 2017 and at Jazz Pharmaceuticals, Inc. from 2004 until June 2015. Earlier in his career, Mr. Rothman served in senior roles at ICON Clinical Research, leading strategic business development and regional operations. Additionally, he has held positions in clinical research, operations and development at Anergen Inc., Genentech, Inc. and Procter & Gamble Pharmaceuticals. Mr. Rothman received his B.S. in Biology from Albright College.

Christine Zedelmayer, 53,54, has served as our Senior Vice President, Chief Operating Officer since January 2020. Ms. Zedelmayer served as our Vice President of Operations from February 2018 through December 2019. Prior to Equillium, Ms. Zedelmayer owns and was owner andpreviously principal consultant at Centerra Consulting, LLC, a project management and investor relations consulting firm focused on life sciences, from 2012 to 2018, where she led strategic business development projects for clients and served as head of investor relations for a variety of medical device companies. Prior to Centerra, from 2003 to 2012, Ms. Zedelmayer held a variety of roles at Amylin Pharmaceuticals, Inc., a publicly-held biopharmaceutical company, including Senior Director of Alliance Management, where she led the global collaboration with Eli Lilly and as Executive Director of Investor Relations. Before joining Amylin, Ms. Zedelmayer held various leadership positions within project management at Amgen Inc., a publicly-held biopharmaceutical company, Ligand Pharmaceuticals, Inc., a publicly-held biopharmaceutical company, and Hybritech, Inc., a privately-held medical diagnostics company. Ms. Zedelmayer received her B.S. in Electrical Engineering from San Diego State University and an M.B.A. with Finance emphasis from California Lutheran University.

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DELINQUENT SECTION 16(a) REPORTSEXECUTIVE AND DIRECTOR COMPENSATION

Section 16(a)We are a “smaller reporting company” under Item 10 of Regulation S-K promulgated under the Exchange Act, requiresand the Company’s directors and executive officers, and persons who own more than ten percent of a registered class of the Company’s equity securities,following compensation disclosure is intended to filecomply with the SEC initial reports of ownership and reports of changes in ownership of common stock and other equity securities of the Company. Officers, directors and greater than ten percent stockholders are required by SEC regulation to furnish the Company with copies of all Section 16(a) forms they file.

To the Company’s knowledge, based on a review of the copies of such reports filed on the SEC’s EDGAR system and written representations that no other reports were required, during the fiscal year ended December 31, 2022, all Section 16(a) filing requirements applicable to smaller reporting companies. Although the rules allow us to provide less detail about our executive compensation program, the Compensation Committee is committed to providing the information necessary to help stockholders understand its officers, directors and greater than ten percent beneficial owners were complied with, exceptexecutive compensation-related decisions. Accordingly, this section includes supplemental narratives that a Form 3 filing was inadvertently filed late by Barbara Troupin, M.D. anddescribe the following Form 4 filings were inadvertently filed late: (i) stock option to purchase 325,000 shares granted to Bruce D. Steel on January 19, 2022, (ii) stock option to purchase 125,000 shares granted to Stephen Connelly, Ph.D. on January 19, 2022, (iii) stock option to purchase 125,000 shares granted to Christine Zedelmayer on January 19, 2022, (iv) stock option to purchase 125,000 shares granted to Jason A. Keyes on January 19, 2022, (v) stock option to purchase 125,000 shares granted to Joel Rothman on January 19, 2022, (vi) stock option to purchase 38,000 shares granted to Daniel M. Bradbury on March 1, 2022 and (vii) stock option to purchase 40,000 shares granted to Dr. Troupin on March 1, 2022. There were no failures to file a required form.

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