Proxy Statement (Form DEF 14A)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☑

Filed by a Party other than the Registrant ☐

Check the appropriate box:

REPLIGEN CORPORATION

(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):

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Notice of 2026 Annual Meeting of Shareholders

Important Notice Regarding the Internet Availability of Proxy Materials

for the Stockholder Meeting to Be Held on May 14, 2026

WHO CAN VOTE

Shareholders of Repligen Corporation's Common Stock as of the close of business on March 16, 2026 (our "Record Date"). It is important that your shares be represented and voted at the 2026 Annual Meeting of Shareholders (the "Annual Meeting"). Whether or not you plan to attend the virtual Annual Meeting, please complete and return the enclosed proxy card in the envelope provided or vote by internet or telephone pursuant to instructions provided with the proxy card.

NOTICE AND ACCESS

We are mailing a Notice of Internet Availability of Proxy Materials (the "Notice") to our shareholders instead of paper copies of our Proxy Statement. The Notice contains instructions on how to access our Proxy Materials over the internet. The Notice also contains instructions on how shareholders can receive a paper copy of our Proxy Materials, free of charge, including this Proxy Statement and proxy card.

Our Annual Report to Shareholders, containing a letter from our President and Chief Executive Officer and financial statements for the fiscal year ended December 31, 2025 (the "2025 Annual Report"), is also being provided together with this Proxy Statement to all stockholders entitled to vote at the Annual Meeting.

HOW TO VOTE

Our Annual Meeting will again be held in a virtual meeting format only, via the internet, with no physical in-person meeting. At our virtual Annual Meeting, shareholders will be able to attend, vote and submit questions as set forth in this section.

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Voting instructions are the same for registered shareholders (shares are registered in your name with Repligen's transfer agent, American Stock Transfer) and beneficial owners (shares are held in a stock brokerage account or by a bank or other holder of record). Here's how to vote prior to the Annual Meeting:

You may also vote at the Annual Meeting via www.virtualshareholdermeeting.com/RGEN2026. You will need the 16-digit control number included with these proxy materials to vote electronically, to vote by phone, and/or to attend the virtual Annual Meeting. A technical support telephone number will be posted on the Annual Meeting login page so that you can call if you encounter any difficulties accessing the Annual Meeting during the check-in or during the meeting.

Execution of a proxy card, or voting by telephone or via the internet prior to the Annual Meeting, will not in any way limit a shareholder's right to attend the virtual Annual Meeting and vote during the meeting.

HOW TO SUBMIT QUESTIONS

If you are a shareholder of record as of our Record Date, you may ask questions during the Annual Meeting. To do so, you will need to have your 16-digit control number available. During the formal portion of the meeting, your questions must be related to proposals listed under "Voting Matters" above, and more specifically to the particular proposal being discussed at the time. To ask a question during the Annual Meeting, click the Q&A button on the virtual meeting platform and enter your question in the text box. If questions submitted are repetitive as to a particular topic, the Chairperson of the meeting may limit discussion on such topic. We will also hold a question-and-answer period following the formal portion of the meeting, as time permits, during which time we welcome questions not relating to specific proposals.

DATE OF MAILING

It is anticipated that the Notice will be first sent or given to our shareholders on or about April 2, 2026. At this time, the Notice, the Proxy Statement, proxy card, and the 2025 Annual Report will be available for viewing, printing, and downloading at www.proxyvote.com.

By Order of the Board of Directors

Jason K. Garland

Chief Financial Officer

April 2, 2026

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PROXY STATEMENT SUMMARY

We are furnishing this Proxy Statement and the related proxy materials (collectively, the "Proxy Statement") in connection with the solicitation by our Board of Directors ("Board") of proxies to be voted at the 2026 Annual Meeting of Shareholders (the "Annual Meeting") and at any adjournment or postponement thereof. We are providing these materials to the holders of record of our Common Stock as of the close of business on March 16, 2026, and are first making available or mailing the materials on or about April 2, 2026. This summary highlights information contained elsewhere in the Proxy Statement. As this summary does not contain all the information that you should consider in connection with the Annual Meeting, we recommend that you read the entire Proxy Statement carefully before voting.

References throughout the Proxy Statement to "Repligen Corporation", "Repligen", "we", "us", "our", or the "Company" refer to Repligen Corporation and its subsidiaries, taken as a whole, unless the context otherwise indicates.

VOTING MATTERS

Please see the sections titled "General Annual Meeting Information" on page 55and "Additional Information" on page 57for important information about the proxy materials, including voting methods, vote requirements for adoption of each proposal, effect of abstentions and the deadlines to submit shareholder proposals and director nominations for next year's Annual Meeting of Shareholders.

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OUR DIRECTOR NOMINEES

You are being asked to vote on the election of the following nine (9) nominees to our Board. All directors are elected annually by the affirmative vote of a majority of votes cast. The chart below summarizes our director nominees' personal information and current committee memberships. You can find detailed information about each director nominee's background, skill sets and areas of expertise later in this Proxy Statement.

BOARD COMPOSITION

We continuously evaluate our director skill sets and expertise for alignment with Repligen's strategic goals. Our independent directors bring extensive experience in areas that are critical to the Company's strategy and long-term success, such as biopharmaceutical manufacturing, global and commercial operations, and finance. Below we highlight the key skills and experiences of our director nominees that are critical to Repligen's success.

In addition to breadth of skills and experience, we believe in establishing and maintaining a Board that includes various demographics because having multiple perspectives and experiences improves the quality of dialogue, contributes to more effective decision-making on behalf of the Company and its shareholders, and enhances the overall chemistry and collaborative culture in the boardroom.

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CORPORATE GOVERNANCE HIGHLIGHTS

Repligen is committed to implementing and maintaining effective corporate governance practices that further long-term shareholder value, promote the Board's accountability, and align the interests of our executive team with those of our shareholders.

The following represent the key elements of our corporate governance programs:

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SHAREHOLDER ENGAGEMENT

We actively seek and highly value the views and insights of our shareholders. We meet regularly with our shareholders through an ongoing schedule of investor discussions, in-person meetings, conferences, non-deal roadshows and other events. In addition to our traditional investor relations outreach efforts focused on analysts and portfolio manager communications, we engage with shareholder stewardship and proxy governance teams to discuss proxy proposals, overall governance and executive compensation programs, and sustainability reporting and initiatives.

Our shareholder engagement activities have guided certain Board meeting agendas and have led to governance enhancements addressing the issues that matter most to our shareholders. We consider this ongoing engagement process important in creating long-term value, and maintaining a culture of integrity, compliance and sustainability.

Conversations with investors and analysts in 2025 and into 2026 covered a wide range of topics, including the outlook for revenue growth and margin expansion in the near- and long-term. In addition, these discussions centered around our commercial strategy, new product launches, mergers and acquisitions, fit-for-growth investments, the biologics and new modalities end-markets, and the macro backdrop, among other areas.

SUSTAINABILITY - ENVIRONMENTAL, SOCIAL AND GOVERNANCE MATTERS

We believe our commitment to sustainability topics across all our global facilities matters and is an important part of creating long-term business value for all stakeholders. We are deeply committed to corporate responsibility and transparency, and we continue to factor sustainability into our business decisions and integrate its core principles into our daily operations. Together, we are advancing our sustainability initiatives and taking steps to engage stakeholders throughout our upstream and downstream value chain.

To view or download our most recent 2024 sustainability report, "Perspectives on Progress" and/or to access our 2024 reporting frameworks indexes document, please visit repligen.com/company/sustainability.

Sustainability Oversight

Our commitment to sustainability oversight at both the Board and management levels reflects the importance we place on our sustainability policies and programs to support our long-term strategic plan. In 2025, the Board transferred oversight of the sustainability function to the Audit Committee to better align strategies and to support increasing sustainability-related regulatory requirements. The Audit Committee meets regularly and reviews and advises on strategy, initiatives and reporting. For more details about our Sustainability Oversight hierarchy, please see the section titled"Sustainability Oversight" on page 21.

EXECUTIVE COMPENSATION HIGHLIGHTS

Repligen's compensation philosophy is to provide compensation that will attract and retain high-performing talent in our industry, motivate the Company's executive officers to create long-term, enhanced shareholder value and provide a fair reward for robust effort. The Company believes that the compensation of its executive officers should align the executive officers' interests with those of the shareholders and focus executive officer behavior not only on the achievement of near-term corporate goals, but also on the achievement of long-term business objectives and strategies. For more on compensation philosophy see the section titled "Executive Compensation" beginning on page 31.

Compensation Earned

The table below sets forth the compensation that we paid to, or that was earned by or granted to the Company's President and CEO, Chief Financial Officer ("CFO"), Chief Operating Officer ("COO"), Senior Vice President, Research & Development and Senior Vice President, Chief Product Officer ("CPO") in 2025, all five of whom were serving as executive officers as of December 31, 2025 . We

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refer to these individuals as NEOs throughout the Proxy Statement. For more information on the total compensation see "Executive Compensation Tables - 2025 Summary Compensation Table" on page 38.

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The charts below reflect the allocation of base salary, short-term (cash) incentive compensation and long-term (equity) incentive compensation earned by the NEOs in 2025.

2025 Summary Compensation Allocations

Long-term Equity Incentive Breakout for NEOs

We believe that the mix of time-based and performance-based equity awards under our long-term incentive compensation program provides balance to the program, motivates our executives to drive organizational achievement of our near- and long-term corporate goals and aligns the interests of our executive officers with those of our shareholders.

As shown in the graph below, the target split of the annual long-term equity incentive compensation awards made to our NEOs based upon dollar value is 25% performance-based restricted stock units ("PSUs"), 25% stock options subject to time-based vesting, and 50% restricted stock units subject to time-based vesting ("RSUs"). Our Compensation Committee annually reviews our long-term equity incentive program and has determined that the current composition and weightings remain appropriate in furthering our objective of recruiting and retaining top talent in our industry at this time.

The PSU awards granted in 2025 are only earned if we achieve specific three-year revenue growth goals or "Base Organic Revenue Growth" and three-year Adjusted Return on Invested Capital ("Adjusted ROIC"), which are set at challenging levels and weighted at 50% each with cliff vesting after three years based on performance.

Long-term Equity Incentive Payout for NEOs for 2025

In 2023, we granted PSU awards subject to a three-year performance period ending December 31, 2025. As shown in the table below, these PSU awards were not earned due to not achieving the organic revenue growth goal or Adjusted ROIC goal for the PSU awards.

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The following table presents the performance goals and actual achievement for the 2023-2025 program:

We have granted our NEOs performance-based equity awards each year since 2019 and we anticipate that we will continue to include such equity awards as part of our long-term incentive compensation program going forward.

BUSINESS & FINANCIAL HIGHLIGHTS 2025

In 2025, we delivered on the five strategic priorities we outlined at the beginning of the year:

Accelerated Growth with a Transformed Customer Experience.

We returned to double-digit growth in 2025 with 16% growth on both a reported and organic non-COVID basis. This was driven by broad momentum across our portfolio, expansion of our customer base, and strength across all geographies. Consumables led the way with 20%+ growth, while equipment was roughly flat year-over-year, though we saw strong traction in our Analytics offerings. We continue to capitalize on our broad portfolio and cross-selling opportunities with our key accounts team, which is focused on approximately 20 large pharma and CDMO accounts, with the objective of further penetrating these accounts by increasing both the number of product lines they purchase and their overall volume. We are now selling 2.5 times as many product lines to these customers versus 2019. In addition, our commercial team is incentivized to cross-sell our entire portfolio. We believe we are early in the penetration of these opportunities. In 2025, we made notable progress on our Asia-Pacific (APAC) strategy as we onboarded a new Head of APAC and GM of China. We will continue to invest in our APAC team in 2026 given the growing activity in this region. Finally, our investments in services translated to accretive growth in 2025. We have a high attachment rate for services in our Analytics franchise and are working to replicate this success across the rest of our capital equipment portfolio.

Expanded Margins.

In 2025, we balanced key investments in the business, while expanding adjusted operating margin by 0.9% to 13.8%. We expanded adjusted gross margin by approximately 2.2%, driven by volume and price, which offset inflation, tariff, and mix headwinds. While foreign currency was favorable, this was offset by dilution from M&A, which weighed on operating margin expansion. Net of foreign currency and M&A, we expanded organic adjusted operating margins by 2.4%. We continue to believe our acquisitions of Tantti and our upstream PAT portfolio are key to our long-term strategy. In 2025, we made important investments in our commercial team,

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legal transformation, finance and IT leadership, along with AI and infrastructure investments. These are critical to ensure we have a scalable foundation to support the growth we see in coming years. We expect to generate increasing operating leverage in coming years to drive margin expansion.

Launched New Products.

We had an active year of new product launches in 2025 across our franchises. In Analytics, we launched our SoloVPE PLUS, the next generation of our SoloVPE with increased accuracy and faster read-out times. We believe this upgrade cycle represents a multi-year growth opportunity for us. In filtration, we launched our new Proconnex® MixOne single-use mixer. We began demos in 2025 and expect to deliver our first placements in 2026. In proteins, we launched a variety of new resins including three new resins in December 2025: AVIPure® HiPer™AAV9, AVIPure® HiPer™AAV8, and HiPer™QA. We are also seeing continuing traction with custom resins developed by Avitide and Tantti.

Acquired Upstream PAT Portfolio and Integrated Tantti.

In 2025, we executed on our M&A roadmap. In March, we announced the acquisition of 908 Devices' desktop portfolio of four devices for upstream bioprocessing process analytical technology (PAT) applications. These devices include the recently rebranded PATsmart™ MAVERICK® and MAVEN® for real-time monitoring and control of critical bioprocess parameters; REBEL, an at-line cell culture media analyzer; and ZipChip®, a high-resolution sample separations device used in the characterization of product quality attributes. In 2025, we made progress on the integration of our upstream portfolio, transitioning manufacturing capabilities to Marlborough, while cross-training our upstream and downstream Analytics teams. This has resulted in a growing funnel of opportunities. In 2025, we also made progress on our integration of Tantti. In July, we announced a strategic partnership with Novasign to develop and integrate Novasign's machine learning and modeling workflow into Repligen filtration systems. As part of the partnership, we made an investment in Novasign to help scale and expand their operations. This furthers our digitization efforts and highlights using minority investments as another capital allocation option. Outside of organic investments in the business, M&A remains our top priority for capital allocation.

Became More Fit for Growth.

In 2025, we made considerable progress on our efforts to become more "fit for growth" and to ensure we have the right foundation in place as we look to scale the business in coming years. We made key leadership hires across legal, finance, and IT. In addition, we made significant investments in our business systems to ensure we are building the right tools and processes to scale the business. This included initial AI investments across our legal and supply chain functions. Looking ahead, we will continue to further build our bench and make targeted system investments in IT modernization, financial planning, and lifecycle product management. In addition, we will invest in strategic transformation initiatives, including projects that can help drive margin expansion.

Sustainability

At Repligen, our sustainability strategy is closely linked to how we build a resilient, high-performance, and low-risk business. In 2025, we continued to advance these efforts. A defining milestone in 2025 was the completion of Repligen Corporation's first enterprise-level Double Materiality Assessment, aligned with emerging European Sustainability Reporting Standards. This work focused on the sustainability topics most relevant to value creation, risk management, and regulatory readiness, and reinforced the importance of integrating sustainability considerations into business planning, decision-making, and investments. Our current sustainability report, and a frameworks index can be downloaded from our website at repligen.com/company/sustainability.

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SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS, DIRECTORS AND MANAGEMENT

The following table sets forth certain information regarding beneficial ownership of shares of our Common Stock as of March 16, 2026 by: (i) each person who is known by the Company to beneficially own more than 5% of the outstanding shares of Common Stock; (ii) each director or nominee of the Company; (iii) each named executive officer of the Company; and (iv) all directors nominees and executive officers of Repligen as a group. The business address of each director and executive officer is Repligen Corporation, 41 Seyon Street, Building #1, Suite 100, Waltham, Massachusetts 02453.

* Less than one percent

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PROPOSAL 1

ELECTION OF DIRECTORS

DIRECTOR NOMINEES

There are nine (9) nominees for director, all of whom are current directors of Repligen that have been nominated by the Nominating and Corporate Governance ("N&CG") Committee and the Board of Directors ("Board") for re-election.

If elected, each of the director nominees will hold office until the 2027 Annual Meeting of Shareholders and until his or her successor has been duly elected and qualified, or until his or her earlier death, resignation or removal.

Shares represented by all proxies received by the Board and not marked or voted to abstain from voting for any individual director or for any group of directors will be voted, unless otherwise indicated, FOR the election of the nominees named above. Proxies may not be voted for a greater number of persons than the number of nominees named. The Board knows of no reason why any nominee should be unable or unwilling to serve, but if any nominee should be unable or unwilling to serve, proxies will be voted in accordance with the judgment of the persons named as attorneys-in-fact on the proxy cards with respect to the directorship for which that nominee was unable or unwilling to serve.

Proposal 1 relates solely to the election of the nine (9) above-named directors nominated by the Company and does not include any other matters relating to the election of directors, including without limitation, the election of directors nominated by any shareholders of the Company.

The Board unanimously recommends a vote FOR each of the nominees for election as directors of the Company. If authorized proxies are submitted without specifying an affirmative or negative vote on any proposal, the shares represented by such proxies will be voted in favor of the Board's recommendations.

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OCCUPATIONS OF DIRECTORS AND EXECUTIVE OFFICERS

Repligen's executive officers are appointed by, and serve at the discretion of, the Board. Each executive officer is a full-time employee of Repligen. The current directors, including director nominees, and executive officers of Repligen as of March 16, 2026 are as follows:

BIOGRAPHICAL INFORMATION

The following paragraphs provide information about the Company's continuing directors and executive officers. The information presented includes information about each director's specific experience, qualifications, attributes and skills that led the Board to the conclusion that he or she should serve as a director.

Executive Officers

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CERTAIN RELATIONSHIPS AND RELATED PERSONS TRANSACTIONS

No family relationship exists among the officers and directors of Repligen. The Audit Committee conducts an appropriate review of all related party transactions for potential conflict of interest situations on an ongoing basis, and the approval of the Audit Committee is required for all such transactions. The term "related party transactions" shall refer to transactions required to be disclosed by the Company pursuant to Item 404 of Regulation S-K promulgated by the Securities and Exchange Commission ("SEC").

FMR LLC ("Fidelity") beneficially owned approximately 5.1% of our common stock as of December 31, 2025. Fidelity, or one or more of its affiliates, is the third-party administrator for the Company's equity compensation plan, the Company's 401(k) retirement plan, and the Non-Employee Directors Deferred Compensation Plan and also provides management services for the Company's Health Savings Account and Flexible Spending Account programs. The Company paid Fidelity approximately $172,528 in 2025 related to these services.

There have been no other transactions or series of similar transactions to which we were, or will be, a party in which the amount involved exceeded, or will exceed, $120,000 and in which any director, executive officer, holder of five percent or more of any class of our capital stock or any member of the immediate family of, or entities affiliated with, any of the foregoing persons, had, or will have, a direct or indirect material interest.

CORPORATE GOVERNANCE AND BOARD MATTERS

BOARD INFORMATION

Director Independence

The Board of Directors ("Board") has determined that each of the directors who has served during the fiscal year ended December 31, 2025 and each of the nominees for director at the 2026 Annual Meeting of Shareholders (the "Annual Meeting"), with the

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exception of Mr. Loeillot, has no material relationship with the Company and is independent within the meaning of the director independence standards of The Nasdaq Stock Market LLC ("Nasdaq"). Furthermore, the Board has determined that each member of the Audit Committee, the Compensation Committee and the Nominating and Corporate Governance ("N&CG") Committee of the Board is independent within the meaning of Nasdaq's director independence standards and that each member of the Audit Committee meets the heightened director independence standards of the Securities and Exchange Commission ("SEC") for audit committee members.

Board Leadership Structure

In 2025, the Board was led by its Executive Chair, Tony J. Hunt, alongside Lead Independent Director, Karen A. Dawes. Dr. Madaus, who is currently serving as the Chair of the Board, succeeded Mr. Hunt, following his previously announced retirement in March 2026. Mr. Loeillot will continue to serve as the Company's principal executive officer in his role as Chief Executive Officer. The Board has determined Dr. Madaus is an independent member of the Board under the rules and regulations of the Securities and Exchange Commission and the Nasdaq Stock Market. The Board believes that the new structure will continue to enhance the accountability of the executive leadership team to the Board and strengthen the Board's independence from management. The Board recognizes that, depending on the circumstances, other leadership models might be appropriate and, accordingly, the Board periodically reviews its leadership structure.

Executive Sessions

The Board holds executive sessions of the independent directors at each regularly scheduled Board meeting and/or as deemed necessary by the Chair of the Board. Executive sessions do not include any employee directors of the Company, and the Chair of the Board is responsible for chairing the executive sessions.

Director Nomination Policies

Director Qualifications

The N&CG Committee is responsible for selecting and recommending nominees for election as directors to the Board. The full Board participates in an annual Board effectiveness assessment, which includes evaluating the appropriate qualities, skills and characteristics of current Board members and identifying skills and qualifications desired for director nominees. These assessments include consideration of the following minimum qualifications that the N&CG Committee believes must be met by all directors:

The N&CG Committee also considers numerous other qualifications, skills and characteristics when evaluating director nominees, such as:

These factors and others are considered useful by the Board and are reviewed in the context of an assessment of the perceived needs of the Board at a particular point in time.

The N&CG Committee considers candidates for Board membership, including those suggested by shareholders, applying the same criteria for all candidates. If the N&CG Committee identifies a need to replace a current member of the Board, to fill a vacancy on the Board, or to expand the size of the Board, it considers candidates from a variety of sources including third-party search firms that

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assist in identifying, evaluating and conducting due diligence on potential director candidates. For all potential candidates, our N&CG Committee will consider all factors it deems relevant, including those enumerated above.

Board Composition

The N&CG Committee is committed to having an inclusive Board and considers a variety of candidate attributes, including whether a candidate, if elected, assists in achieving a mix of directors who represent varied backgrounds and experience. A Board that includes varying perspectives, personal and professional background, knowledge and experience, is important because we believe having varying perspectives and a breadth of experience improves the quality of deliberations, contributes to more effective decision-making on behalf of the Company and its shareholders and enhances the overall chemistry and collaborative culture in the boardroom. Accordingly, the N&CG Committee is committed to actively seeking out Board candidates who are highly qualified women, minorities, and individuals with other varying backgrounds, skills and experience.

Process for Identifying and Evaluating Director Nominees

The Board is responsible for selecting and nominating nominees for election as directors, but delegates the selection and nomination process to the N&CG committee, with the expectation that other members of the Board or members of management will take part in the process as appropriate.

Generally, the N&CG Committee identifies candidates for director nominees in consultation with Board members and management, through the use of search firms or other advisers, through the recommendations submitted by shareholders or through such other methods as the N&CG Committee deems to be helpful in identifying candidates. Consistent with historical practices and our ongoing efforts in inclusivity, we target a wide range of candidates. Once candidates have been identified, the N&CG Committee confirms that the candidates meet all of the minimum qualifications for director nominees established by the N&CG Committee. The N&CG Committee may gather information about the candidates through interviews, questionnaires, background checks, or any other means that the N&CG Committee deems to be helpful in the evaluation process. The N&CG Committee meets as a group to discuss and evaluate the qualities and skills of each candidate, both on an individual basis and taking into account the overall composition and needs of the Board. Based on the results of the evaluation process, the N&CG Committee recommends candidates to be interviewed by other Board directors and ultimately recommends final candidates for the Board's approval as director nominees for election to the Board. The N&CG Committee also recommends candidates for the Board's appointment to the committees of the Board.

Procedures for Recommendation of Nominees by Shareholders

The N&CG Committee will consider director candidates who are recommended by the shareholders of the Company. Shareholders who meet the applicable eligibility requirements under the proxy access provision of our By-laws and who wish to include nominees for our Board in the Company's Proxy Statement for the 2027 Annual Meeting of Shareholders, or shareholders who wish to make a proposal at the 2027 Annual Meeting of Shareholders (other than a proposal made pursuant to Rule 14a-8 issued under the Securities Exchange Act of 1934, as amended ("Exchange Act") or pursuant to the proxy access provision of our By-laws), must in each case deliver any such recommendation not later than the close of business on the 60th day, nor earlier than the close of business on the 90th day, prior to the first anniversary of the preceding year's Annual Meeting of Shareholders. Shareholders, in submitting recommendations to the N&CG Committee for director candidates, shall follow the following procedures:

Such recommendation for nomination should be in writing and include the following:

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Nominations must be sent to the attention of the Corporate Secretary of the Company by the method listed below:

Repligen Corporation

Attn: Corporate Secretary

41 Seyon Street

Building #1, Suite 100

Waltham, MA 02453

The Corporate Secretary of the Company will promptly forward any such nominations to the N&CG Committee. Once the N&CG Committee receives the nomination of a candidate, the candidate will be evaluated and a recommendation with respect to such candidate will be delivered to the Board. Nominations not made in accordance with the foregoing policy shall be disregarded by the N&CG Committee and votes cast for such nominees shall not be counted.

In addition to satisfying the above requirements, to comply with the SEC's universal proxy rules, shareholders who intend to solicit proxies in support of director nominees other than the Company's nominees must provide notice that sets forth the information required by Rule 14a-19 under the Exchange Act no later than March 15, 2027.

The Company recognizes the importance of a shareholder's ability to nominate directors to the Company's Board. As part of the Company's commitment to providing a director nomination process that is fair and equitable to all nominating shareholders, the Company's Corporate Governance Guidelines provide that the Board will not, without shareholder consent, adopt any amendments to our By-laws that would require a nominating shareholder to: (i) deliver director nominations more than 90 days prior to the first anniversary of the prior year's Annual Meeting of Shareholders; (ii) disclose to the Company such shareholder's plans to nominate candidates to the board of directors of other public companies, or disclose prior proposals or director nominations that such shareholder privately submitted to other public companies; or (iii) disclose information to the Company about a nominating shareholder's limited partners or business associates.

Shareholder Communication Policies

The Board provides to every shareholder the ability to communicate with the Board, as a whole, and with individual directors on the Board through an established process for shareholder communication (as that term is defined by the rules of the SEC) as follows:

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For communications directed to the Board as a whole, shareholders may send such communication to the attention of the Chair of the Board through the method below:

Repligen Corporation

Attn: Chair of the Board of Directors

41 Seyon Street

Building #1, Suite 100

Waltham, MA 02453

For shareholder communications directed to an individual director in his or her capacity as a member of the Board, shareholders may send such communications to the attention of the individual director through the method below:

Repligen Corporation

Attn: [Name of Individual Director]

41 Seyon Street

Building #1, Suite 100

Waltham, MA 02453

The Company will forward any such shareholder communication to the Chair of the Board, as a representative of the Board, and/or to the director to whom the communication is addressed on a periodic basis. The Company will forward such communication by certified U.S. Mail to an address specified by each director of the Board for such purposes or by secure electronic transmission.

DirectorAttendance Policy

The Board's policy is that all directors and director nominees attend the Company's Annual Meeting in person, via teleconference, or via other virtual means. All members who were on the Board as of May 15, 2025 attended the 2025 Annual Meeting of Shareholders.

Stock Ownership Guidelines and Insider Trading Policy

The Board has adopted share ownership guidelines relating to ownership of the Company's securities by the Company's named executive officers ("NEOs") and non-employee directors. Subject to the terms of the policy, (i) the CEO is required to acquire over a five-year period and hold shares of Common Stock of the Company equal to five times his or her base salary as of a specified measuring date, (ii) each of the Company's NEOs other than the CEO is required to acquire over a five-year period and hold shares of Common Stock of the Company equal to one times his or her base salary as of a specified measuring date, and (iii) each of the Company's non-employee directors is required to acquire over a five-year period and hold shares of Common Stock of the Company equal to four times the Company's annual cash retainer paid to each such non-employee director. Restricted stock and restricted stock units subject to time-based vesting (whether or not vested as of the measurement date) are included in the number of shares owned, but unexercised stock options (regardless of whether they are vested or unvested) and performance-based restricted stock units are not included in the total number of shares owned by the NEOs or directors for purposes of the share ownership policy. All directors and NEOs currently comply with their respective share ownership requirements or are on track to meet them within the five-year period.

We have adoptedan Insider Trading Policy governing the purchase, sale and/or other dispositions of our securities by our directors, officers and employees. Under the Company's insider trading policy, employees, including executive officers and non-employee directors, are not permitted to engage in the following transactions with respect to the Company's stock: selling any of the Company's securities that are not owned by such insider at the time of sale and holding the Company's stock in an account that is, or is linked to, a margin account. In addition, the following transactions are not permitted without pre-approval of the Company's Audit Committee: buying or selling puts, calls or other derivatives of the Company's securities or any derivative securities that provide the economic equivalent of ownership of any of the Company's securities; engaging in any hedging transaction with respect to the Company's securities; or pledging Company securities as collateral for a loan. Gifts (transfer of the Company's stock without consideration) are subject to the same restrictions as all other trades and are prohibited during a period when the insider is not permitted to trade.

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It is the Company's policy to comply with applicable insider trading laws, rules and regulations, and any exchange listing standards when engaging in transactions in Company securities. Our Insider Trading Policy is reasonably designed to promote compliance with insider trading laws, rules and regulations, as well as applicable listing standards. A copy of the Company's Insider Trading Policy is filed as Exhibit 19.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2025.

Code of Business Conduct & Ethics

Repligen has adopted a Code of Business Ethics & Conduct as its "code of ethics" as defined by regulations promulgated under the Securities Act of 1933, as amended, and the Exchange Act (and in accordance with the Nasdaq requirements for a "code of conduct"), which applies to all of the Company's directors, officers and employees, including its principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. A current copy of the Code of Business Conduct & Ethics is available at the "Company" - "Investors" - "Investors Overview" - "Corporate Governance" - "Policies and Charters" section of the Company's website at repligen.com. A copy of the Code of Business Conduct & Ethics may also be obtained free of charge from the Company upon a request directed to Repligen Corporation, Attention: Investor Relations, 41 Seyon Street, Building #1, Suite 100, Waltham, MA 02453. The Company will promptly disclose any substantive changes in or waivers, along with reasons for the waivers, of the Code of Business Conduct and Ethics granted to its executive officers, including its principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, and its directors by posting such information on its website at repligen.com under "Company" - "Investors" - "Investors Overview" - "Corporate Governance."

The Board'sRole in Risk Oversight

The Company's management is responsible for assessing and managing risk and the Board oversees and reviews the Company's risk management process. This oversight by the Board is primarily accomplished through its committees and through management's reporting processes, including having the Board receive regular reports from members of senior management on areas of material risk to the Company, including operational, financial, legal and regulatory, strategic, and governance risks. In addition, at the beginning of each Board meeting, the CEO provides a status update on the Company and addresses any areas of risk in an executive session. A full risk management assessment is performed and presented to the Board periodically.

The committees of the Board execute their oversight responsibility for risk management as follows:

We will continue to uphold our strong corporate governance, shareholder rights and executive compensation programs. Our Board also oversees our executive and Board succession planning strategies.

SUSTAINABILITY - ENVIRONMENTAL, SOCIAL AND GOVERNANCE MATTERS

We believe our commitment to sustainability topics across all our global facilities matters and is an important part of creating long-term business value for all stakeholders. We are deeply committed to corporate responsibility and transparency, and we continue to factor sustainability into our business decisions and integrate its core principles into our daily operations.

The actions we have taken to build and implement our robust sustainability strategy are supported by core pillars focused on Environmental, Social and Governance ("ESG") issues, and demonstrates our long-term commitment to being a responsible global

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corporate citizen. Together, we are advancing our ESG initiatives and taking steps to engage stakeholders throughout our upstream and downstream value chain.

We are also taking bold steps to engage key stakeholders throughout our upstream and downstream value chain to educate and inspire them to advance related initiatives for even greater impact and transparency. To view or download our most recent 2024 corporate sustainability report, "Perspectives on Progress" and its associated reporting framework indices, or any of our previous reports, please visit repligen.com/company/sustainability.

Oversight

Our commitment to sustainability oversight at both the Board and management levels reflects the importance we place on ESG-driven policies and programs to support our long-term strategic plan. Below is our sustainability governance hierarchy:

Sustainability

At Repligen, sustainability is closely linked to how we build a resilient, high-performance, and low-risk business. In 2025, the company continued to advance this pragmatic approach-strengthening governance, improving transparency, and investing in the systems and capabilities required to support long-term growth. These efforts also reflect a deliberate focus on preparing for evolving mandatory reporting and compliance requirements, positioning Repligen to meet future obligations with confidence. Progress was made across environmental, social, and governance priorities most material to the business and to stakeholders, while maintaining consistency with the voluntary reporting practices and frameworks Repligen has adopted over recent years.

A defining milestone in 2025 was the completion of Repligen Corporation's first enterprise-level Double Materiality Assessment, aligned with emerging European Sustainability Reporting Standards. This work sharpened focus on the sustainability topics most relevant to value creation, risk management, and regulatory readiness, and reinforced the importance of integrating sustainability considerations into business planning, decision-making and investments. In parallel, oversight of sustainability reporting and related controls was transitioned to the Audit Committee, reflecting the increasing convergence of financial and sustainability disclosures and reinforcing rigor, accountability, and alignment with enterprise risk management. These governance enhancements were further supported by the introduction of dedicated corporate policies on Human Rights and Sustainability, formalizing long-standing commitments to ethical conduct, environmental stewardship, and responsible business practices.

As the company looks ahead, Repligen remains committed to achieving net-zero greenhouse gas emissions by 2050 and to advancing sustainability as a driver of business resilience, innovation, and long-term value creation. By embedding sustainability into decision-making, governance, and daily operations, Repligen is better positioned to meet evolving customer expectations, navigate an increasingly complex regulatory landscape, and deliver durable results for stakeholders.

Sustainability Reporting

Our sustainability reporting objective is to provide transparency on how we are advancing our evolving sustainability strategy and how we are contributing to sustainable development. With that objective, we continue to deliver high-quality and comprehensive environmental, social, and governance reporting on topics that we believe are relevant to our customers, shareholders, employees, and community members. Our sustainability report also includes disclosures aligned with the Global Reporting Initiative ("GRI") Universal Standard 2021 and the Sustainability Accounting Standards Board ("SASB") standards, the GHG Protocol and the Task Force on Climate-related Financial Disclosures ("TCFD"). As the reporting framework landscape continues to change, such as the merger of SASB standards into the International Sustainability Standards Board ("ISSB"), the disbanding of TCFD and the release of new European Sustainability Reporting Standards ("ESRS") standards, we will continue to evolve our reporting practices.

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BOARD MEETINGS AND COMMITTEES

The Board of Directors ("Board") met six (6) times during the fiscal year ended December 31, 2025. During the fiscal year ended December 31, 2025: each director attended 100% of each of the total number of meetings of the Board held during their period of service, with the exception of one director, who did not attend one Board meeting. Each director also attended 100% of the meetings held by all committees of the Board on which each director served, with the exception of one director, who did not attend one out of five of the total number of committee meetings applicable to such director. The Board has a standing Audit Committee, Compensation Committee, and Nominating and Corporate Governance ("N&CG") Committee. Each of these standing committees has a charter that has been approved by the Board. Each standing committee reviews the appropriateness of its charter periodically, as conditions dictate, but at least annually.

AUDIT COMMITTEE

The Audit Committee was established in accordance with Section 3(a)(58)(A) of the Securities Exchange Act of 1934, as amended ("Exchange Act"), and currently consists of Mr. Muir, Mses. Dawes, and Eglinton Manner. The Audit Committee is responsible for overseeing the accounting and financial reporting processes of the Company and the audits of the financial statements of the Company and exercising the responsibilities and duties set forth below, including but not limited to:

The Audit Committee met five (5) times during the fiscal year ended December 31, 2025. Mr. Muir currently serves as Chairperson of the Audit Committee. The Board has determined that Mr. Muir qualifies as an "audit committee financial expert" under the rules of the SEC. The Board has determined that each member of the Audit Committee is independent within the meaning of the Nasdaq Stock Market LLC's ("Nasdaq's") director independence standards and the SEC's heightened director independence standards for audit committee members as determined under the Exchange Act.

The Audit Committee operates under a written charter adopted by the Board, a current copy of which is available on the Company's website at repligen.com under "Investors" - "Corporate Governance" - "Policies and Charters."

COMPENSATION COMMITTEE

The Compensation Committee currently consists of Ms. Pax, Messrs. Barthelemy and Muir, and Dr. Mhatre. The Compensation Committee, is responsible (among other duties and responsibilities) for:

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The Compensation Committee met four (4) times during the fiscal year ended December 31, 2025. Ms. Pax currently serves as the Chairperson of the Compensation Committee. The Board has determined that each member of the Compensation Committee is independent within the meaning of the SEC and Nasdaq's director independence standards.

The Compensation Committee operates under a written charter adopted by the Board, which is available on the Company's website at repligen.com under "Investors" - "Corporate Governance" - "Policies and Charters."

NOMINATING AND CORPORATE GOVERNANCE COMMITTEE

The N&CG Committee of the Board currently consists of Dr. Madaus, Dr. Konstantinov, and Ms. Pax. The N&CG Committee met one (1) time during the fiscal year ended December 31, 2025. The N&CG Committee is responsible for:

The N&CG Committee may also consider director nominees recommended by the Company's shareholders as described above.

Dr. Madaus currently serves as the Chairperson of the N&CG Committee. The Board has determined that each member of the N&CG Committee is independent within the meaning of the SEC's and Nasdaq's director independence standards.

The N&CG Committee operates under a written charter adopted by the Board, which is available on the Company's website at repligen.com under"Investors" - "Corporate Governance" - "Policies and Charters."

Other Committees of the Board

Our Board may, as needed or advisable from time to time, form temporary, ad hoc or other standing committees and delegate the authority to oversee, identify, evaluate or negotiate a specific issue, opportunity and function, and to, as appropriate, make recommendations to the full Board. For example, our Board has established a Transaction Committee to oversee, advise on and assist our management and the full Board in considering or pursuing acquisitions, partnering and other business development opportunities.

PROPOSAL 2

RATIFICATION OF THE SELECTION OF OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Audit Committee of the Board of Directors ("Board") has appointed Ernst & Young LLP ("EY"), a registered public accounting firm, to serve as independent auditors for the fiscal year ending December 31, 2026. EY has served as the Company's independent registered public accounting firm since 2002. In accordance with professional standards and the requirements of the Securities and Exchange Commission ("SEC") and the Public Company Accounting Oversight Board, EY periodically changes the personnel who work on the audits of the Company.

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AUDIT AND NON-AUDIT FEES

The following sets forth the aggregate fees billed by EY to the Company and incurred by the Company during the fiscal years ended December 31, 2025 and 2024:

The Audit Committee of the Board has implemented procedures under the Company's Audit Committee Pre-Approval Policy for Audit and Non-Audit Services (the "Pre-Approval Policy"), to ensure that all audit and permitted non-audit services provided to the Company are approved by the Audit Committee. Specifically, the Audit Committee pre-approves the use of EY for specific audit and non-audit services, within approved monetary limits. If a proposed service has not been pre-approved pursuant to the Pre-Approval Policy, then it must be specifically pre-approved by the Audit Committee before EY may provide the services. Any pre-approved services exceeding the limits pre-approved by the Audit Committee must again be pre-approved by the Audit Committee. All of the audit-related and tax and other services provided by EY to the Company for the fiscal year ended December 31, 2025 were pre-approved by the Audit Committee. All non-audit services provided in the fiscal year ended December 31, 2025 were reviewed with the Audit Committee, which concluded that the provisions of such services by EY was compatible with the maintenance of that firm's independence in the conduct of its auditing functions.

In connection with the audit for the fiscal year ended December 31, 2025, there were no disagreements with EY on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedure, which, if not resolved to the satisfaction of EY, would have caused them to refer to such disagreement in connection with their report.

A member of EY is expected to be present at the 2026 Annual Meeting of Shareholders with the opportunity to make a statement if so desired and will be available to respond to appropriate questions.

Accordingly, the Board believes ratification of the appointment of EY as the Company's independent registered public accounting firm for the current year is in the best interests of the Company and its shareholders and recommends a vote FOR the ratification of EY as the Company's independent registered public accounting firm.

AUDIT COMMITTEE REPORT

This report is furnished by the Company's Audit Committee with respect to the Company's financial statements for fiscal year 2025. The Company's management is responsible for the preparation and presentation of complete and accurate financial statements. The independent registered public accounting firm EY is responsible for performing an independent audit of the Company's financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States) ("PCAOB") and for issuing a report on its audit. The Audit Committee oversees and monitors the Company's management and its independent registered public accounting firm throughout the financial reporting process.

The material in this report is not "soliciting material," is not deemed filed with the SEC, and is not to be incorporated by reference in any filing of the Company under the Securities Act of 1933, as amended or under the Securities Exchange Act of 1934, as amended ("Exchange Act"), whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

The Audit Committee currently consists of Mr. Muir, Chairperson, Mses. Dawes and Eglinton Manner. The Audit Committee has the responsibility and authority described in the Repligen Audit Committee Charter, which has been approved by the Board. The Board has determined that the members of the Audit Committee meet the independence requirements set forth in Rule 10A-3(b)(1) under the Exchange Act and the applicable rules of the National Association of Securities Dealers, Inc., and that Mr. Muir qualifies as an "audit committee financial expert" under the rules of the SEC. The Audit Committee oversees the accounting and financial reporting processes of

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the Company and the audits of the financial statements of the Company. Management has the primary responsibility for the financial statements and the reporting process, including the systems of internal controls.

In fulfilling its oversight responsibilities, the Audit Committee reviewed and discussed with management of the Company and EY the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025 ("Form 10-K"), including a discussion of the quality, not just the acceptability, of the accounting principles, the reasonableness of significant judgments and the clarity of disclosures in the financial statements. The Audit Committee also reviewed the Company's quarterly financial statements for the first three fiscal quarters during the fiscal year ended December 31, 2025 and discussed them with both the management of the Company and EY prior to including such interim financial statements in the Company's Quarterly Reports on Form 10-Q. In connection with the Company's Form 10-K for the fiscal year ended December 31, 2025 and the Form 10-Q for each of its first, second and third fiscal quarters of the fiscal year ended December 31, 2025, the Audit Committee discussed the results of the Company's certification process relating to the statements in the Company's Form 10-Qs, as well as financial statements under Sections 302 and 906 of the Sarbanes-Oxley Act. The Audit Committee also discussed with EY the matters required to be discussed by the PCAOB's Auditing Standard No. 1301, Communication with Audit Committees, and the SEC. In addition, the Audit Committee has received from EY the written disclosures and the letter from EY as required by applicable requirements of the PCAOB regarding EY's communications with the Audit Committee concerning independence and has discussed with EY their independence.

The Audit Committee also reviewed management's report on its assessment of the effectiveness of the Company's internal control over financial reporting and EY's report on the effectiveness of the Company's internal control over financial reporting.

The Audit Committee discussed with EY the overall scope and plans for their audit. The Audit Committee met with EY to discuss the results of their examinations, their evaluations of the Company's internal controls, including internal control over financial reporting, and the overall quality of the Company's financial reporting.

The Audit Committee has also evaluated the performance of EY, including, among other things, the amount of fees paid to EY for audit and non-audit services. Based on its evaluation, the Audit Committee has selected EY to serve as the Company's auditors for the fiscal year ending December 31, 2026. The shareholders of the Company are being asked to ratify the selection of EY as the Company's independent public accounting firm in Proposal 2 of this Proxy Statement.

The Audit Committee met five (5) times during the fiscal year ended December 31, 2025. In reliance on the reviews and discussions referred to above, the Audit Committee recommended to the Board that the Company's audited financial statements and management's assessment of the effectiveness of the Company's internal controls over financial reporting be included in Form 10-K, and the Board approved such inclusion.

Respectfully submitted by the Audit Committee,

Glenn P. Muir, Chairperson

Karen A. Dawes

Carrie Eglinton Manner

PROPOSAL 3

ADVISORY VOTE ON EXECUTIVE COMPENSATION

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 enables our shareholders to vote to approve, on an advisory basis, the compensation of our named executive officers ("NEOs") as disclosed in this Proxy Statement in accordance with the Securities and Exchange Commission's ("SEC's") rules.

As described in the section titled "Compensation Discussion and Analysis" which begins on page 28and in the accompanying tables and narrative disclosure, our executive compensation programs are designed to motivate our executive officers to create long-term, enhanced shareholder value and provide a fair reward for robust effort. The Company seeks to provide near-term and long-term financial incentives that align the executive officers' interests with those of the shareholders and focus executive officer behavior on the achievement of near-term corporate goals, as well as long-term business objectives and strategies. We believe that this alignment between executive compensation and shareholder interests has driven corporate performance over time.

Our shareholders voted on May 18, 2023, to have advisory votes every year to approve the compensation paid to the Company's NEOs, and we have adopted that approach. The Board of Directors ("Board") and Compensation Committee make executive compensation decisions every year, and our directors look to the annual advisory vote for information to be taken into account when they make decisions with respect to our compensation philosophy, policies and practices.

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Accordingly, we are asking our shareholders to vote FOR the following non-binding, advisory resolution on the approval of the compensation of the Company's NEOs as disclosed in this Proxy Statement:

"RESOLVED, that the shareholders of the Company approve, on an advisory basis, the compensation of the Company's NEOs, as disclosed in this Proxy Statement, including the Compensation Discussion and Analysis, compensation tables and narrative discussion."

We urge you to read the "Compensation Discussion and Analysis"section of this Proxy Statement and the accompanying tables and narrative disclosure for additional details on the Company's executive compensation, including our governance, framework, components, and the compensation decisions for the NEOs for the fiscal year ended December 31, 2025.

As an advisory vote, the results of this vote will not be binding on the Board or the Company. However, the Board and the Compensation Committee value the opinions of our shareholders and will consider the outcome of the vote when making future decisions on the compensation of our NEOs and the Company's executive compensation principles, policies and procedures.

The Board unanimously recommends that shareholders vote FOR approval, on an advisory basis, of the compensation of the Company's NEOs, as disclosed in this Proxy Statement, including the "Compensation Discussion and Analysis", compensation tables and narrative discussion.

COMPENSATION COMMITTEE REPORT

The Compensation Committee of the Board, which is comprised solely of independent directors as defined under the applicable rules of the Nasdaq Stock Market LLC and non-employee directors as defined under Rule 16b-3 under the Securities Exchange Act of 1934, as amended, is responsible for developing executive compensation policies, advising the Board with respect to such policies, and administering the Company's cash and equity incentive plans. The Compensation Committee sets performance goals and objectives for the Chief Executive Officer ("CEO") and the other executive officers, evaluates their performance with respect to those goals and sets their compensation based upon the evaluation of their performance. In evaluating executive officer pay, the Compensation Committee may retain the services of a compensation consultant and consider recommendations from the CEO with respect to goals and compensation of the other executive officers. The Compensation Committee assesses the information it receives in accordance with its business judgment. The Compensation Committee also periodically reviews non-employee director compensation. All decisions with respect to executive compensation are approved by the Compensation Committee and all decisions with respect to director compensation are recommended by the Compensation Committee to the full Board for approval.

The Compensation Committee of the Company has reviewed and discussed the "Compensation Discussion and Analysis"required by Item 402(b) of Regulation S-K promulgated by the SEC with management and, based on such review and discussions, the Compensation Committee recommended to the Board that the "Compensation Discussion and Analysis"be included in this Proxy Statement.

Respectfully submitted by the Compensation Committee:

Margaret A. Pax, Chairperson

Nicolas M. Barthelemy

Rohin Mhatre, Ph.D.

Glenn P. Muir

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COMPENSATION DISCUSSION AND ANALYSIS

Our Compensation Discussion and Analysis describes our executive compensation philosophy and program. The executive compensation tables that follow provide information relating primarily to 2025 compensation decisions for the following named executive officers ("NEOs"):

2025 LEADERSHIP CHANGES

Mr. Douglass was appointed as Senior Vice President, Chief Product Officer, effective December 31, 2025. He previously served as the Company's Senior Vice President, Filtration and Chromatography.

BUSINESS & FINANCIAL HIGHLIGHTS 2025

Information on business and financial highlights of the Company for 2025 can be found in the Proxy Statement Summary in the section titled "Business & Financial Highlights 2025"on page 7.

COMPENSATION PHILOSOPHY

In accordance with the Company's compensation philosophy, the Company provides compensation that the Compensation Committee believes will attract and retain high-performing talent in our industry, motivate the Company's executive officers to create long-term, enhanced shareholder value and provide a fair reward for robust effort.

It is the responsibility of the Compensation Committee of the Board to administer the Company's compensation programs to ensure that they are competitive with other bioprocessing, life sciences research tools, and health care supply industries, and to include incentives that are designed to appropriately drive the Company's continued development to create shareholder value. The Compensation Committee reviews and approves all components of the Company's named executive officer compensation, including base salaries, annual cash incentive compensation, and equity incentive compensation.

COMPENSATION OBJECTIVES

The Company believes that the compensation of its executive officers should align the executive officers' interests with those of the shareholders and focus executive officer behavior not only on the achievement of near-term corporate goals, but also on the achievement of long-term business objectives and strategies.

To achieve these objectives, the Company's compensation program for its executive officers:

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The following features of our compensation programs are designed to protect and promote the interests of our shareholders while aligning executive compensation with performance.

COMPENSATION EVALUATION PROCESS

The Company's executive officer compensation consists of three primary components: base salary, annual cash incentive compensation and equity incentive compensation. Each of these components is intended to complement the others, and taken together, to satisfy the Company's compensation objectives. The Compensation Committee considers a number of factors in setting compensation for its executive officers, including Company performance, the executive's functional performance, experience and responsibilities, and the compensation of executive officers in similar positions in our peer group of companies.

Our Board and executive team actively seek and highly value the views and insights of our shareholders. In evaluating our executive compensation programs for the fiscal year ended December 31, 2025, the Compensation Committee considered the shareholder advisory vote on our executive compensation, or the "say-on-pay" vote, for the fiscal year ended December 31, 2024, which was approved by approximately 93% of the votes cast. The Compensation Committee believes that the shareholders, through this advisory vote, endorsed the compensation philosophies of the Company and, thus, the Compensation Committee maintained the basic structure and design of our executive compensation programs for fiscal year 2025. The Compensation Committee intends to continue to focus on aligning executive compensation programs with the interests of our shareholders and current market practice, including a continued emphasis on pay for performance. We currently hold a "say-on-pay" vote on an annual basis, and our Board intends to continue to do so until at least our next shareholder advisory vote on the frequency of say-on-pay votes to approve our executive compensation, which will occur at our 2029 Annual Meeting of Shareholders.

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Role of Compensation Consultant

In establishing compensation levels for each executive officer, the Compensation Committee has the authority to engage the services of outside experts. In the fiscal year ended December 31, 2025, the Compensation Committee retained Meridian Compensation Partners, LLC ("Meridian"), an independent compensation consulting firm, to assist the Compensation Committee in assessing the competitiveness and effectiveness of the Company's executive compensation programs. In addition, our finance and human resources departments support the Compensation Committee in its work and act in accordance with the direction given to them to administer our compensation programs.

The Compensation Committee has assessed any potential conflicts of interest raised by the work of Meridian pursuant to the Securities and Exchange Commission ("SEC") rules, and has determined that no such conflicts of interest exist.

During the fiscal year ended December 31, 2025 and in March 2026, the Compensation Committee held meetings with management and representatives of Meridian to:

Use of Peer Group to Benchmark Compensation

Meridian provided the Compensation Committee with an analysis of base salary, target bonus, target total cash, long-term incentive value and design, and target total compensation for executives, as well as an analysis of cash and equity compensation for non-employee directors based on data derived from a 16-company compensation peer group. The 2025 peer group was composed of comparable companies in the bioprocessing, life sciences research tools and health care supplies industries with median revenues of $1.1 billion, as compared to the Company's 2025 revenue of $738 million. Based on this selection criteria, the Compensation Committee approved the following peer group for 2025 compensation decisions:

Each year, Meridian, in conjunction with our Compensation Committee, re-evaluates our peer group in light of developments in the market and our industry and the evolution of the Company (e.g., revenue and market capitalization). As a result of this review, the 2025 peer group differs from the 2024 peer group in the following respects: one company was removed from the peer group (Avid Bioservices, Inc.) compared to the prior year. This change was made to improve the alignment of revenue size of the peer group to that of the Company while maintaining companies of similar business focus.

The Compensation Committee uses the peer group compensation data as one of several factors in determining appropriate compensation parameters for base salary, variable cash compensation and equity-based, long-term incentives.

While the Compensation Committee generally targets each NEO's total compensation to be within a competitive range of the 50th to 75th percentile of the peer group, it considers a number of additional factors to determine the appropriate level of each NEO's total compensation and each component of compensation, including Company performance and the relevant executive's

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performance, experience, responsibilities and impact. Due to these other factors, the Compensation Committee may set an NEO's compensation below, at, or above the 50th percentile of the peer group.

EXECUTIVE COMPENSATION

Base Salary

Base salary represents the fixed portion of an executive officer's compensation and is intended to provide compensation for day-to-day performance. The Compensation Committee believes that a competitive base salary is a necessary element of any compensation program that is designed to attract and retain talented and experienced executives. Each executive officer's base salary is initially determined upon hire or promotion based on arms-length negotiations, the executive officer's responsibilities, prior experience, individual compensation history and salary levels of other executives within the Company and similarly situated executives within our peer group. Base salary is typically reviewed annually and may be adjusted based on the executive officer's responsibilities, prior experience, individual compensation history and salary levels of other executives within the Company and similarly situated executives within our peer group. The Compensation Committee believes that the base salaries paid to our executive officers during the fiscal year ended December 31, 2025 achieved the Company's compensation objectives.

Base salaries for the NEOs for 2025 and 2024 are as follows:

Annual Cash Incentive Compensation (Short-Term Incentive) Plan

In 2025, NEOs were eligible to earn cash incentive bonuses under the Company's Annual Cash Incentive Compensation Plan (the "Plan"), to incentivize and reward NEOs for achieving certain performance goals that drive Company performance, align pay and performance, and support the long-term growth of the Company.

The Company's NEOs, other than the CEO, were eligible to receive annual cash incentive compensation based on achievement of (i) Company-wide performance goals (the "Company Objectives") and (ii) performance objectives tied to individual results for their respective functional areas (the "Individual Performance Objectives"). As the Company's current CEO, Mr. Loeillot is responsible for developing Company strategy and overseeing all of the Company's corporate functions, product development and commercial activities. Because of these responsibilities, Mr. Loeillot's incentive payouts are calculated based solely on Company Objectives to closely align his compensation with the Company's performance.

At the beginning of 2025, the Compensation Committee established each NEO's target annual cash incentive compensation (the "Target Award") at a level that represents a meaningful portion of each NEO's cash compensation. In addition, the Compensation Committee set threshold, target and maximum performance goals and related payout levels taking into account annual cash incentive compensation levels for comparable positions within our peer group and our own historical practices. An NEO could earn between 0% and 200% of the NEO's Target Award for achievement of Corporate Objectives, dependent upon the level of achieved performance. After the end of fiscal year 2025, the Compensation Committee evaluated achievement of the Company Objectives and each NEO's Individual Performance Objectives, for those with individual performance objectives, and determined each NEO's annual cash incentive compensation based on such achievement.

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Annual Cash Incentive Compensation (Short-Term Incentive) Plan Protocol

The Compensation Committee administers the Plan:

Selection of 2025 Performance Measures and Goals

Generally, the Company must attain a minimum level of achievement of its Company Objectives for any payment to be made pursuant to the Plan, and the Compensation Committee may, at its discretion, elect to adjust bonuses upward or downward, or not to pay bonuses at all. The Target Award and the weight assigned to Company Objectives and Individual Performance Objectives were determined for each executive officer based upon arms-length negotiations for newly hired executives and the executive officer's position and competitive market data derived from our peer group. The final incentive payout is determined for each executive officer based on the achievement of Company Objectives and Individual Performance Objectives (other than for the CEO, whose annual cash incentive is determined based solely on Company Objectives) defined for each organizational level and position and the Target Award.

Our Company is focused on driving above-industry level growth through internal innovation, acquisitions and expansion of applications for our bioprocessing solutions. With our focus on growth, we believe that adjusted revenue and adjusted earnings per share ("EPS") were relevant targets to reflect topline success, balanced with our ability to leverage investments in research and development ("R&D"), people and capacity. We assigned equal weighting to each of these Company Objectives. We believe our executive team can directly impact these Company Objectives, which drive shareholder value. The Company Objectives are designed to be challenging, yet reasonably achievable at target. Threshold and maximum levels are designed based on past performance and current annual planned scenarios to ensure alignment and maximized performance and motivation by employees and executive team.

Company Objectives

For the 2025 Plan, the Compensation Committee set the following Company Objectives and related payout levels:

The payout curve has a non-linear interpolation between 80% and 120% performance.

The payout curve has a linear interpolation between 70% and 130% performance.

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The calculations for adjusted revenue and adjusted EPS, on which achievement of Company Objectives is determined, differ from calculations for reported revenue and reported EPS, both determined in accordance with Generally Accepted Accounting Principles in the United States or "U.S. GAAP", set forth in the Company's Annual Report on Form 10-K ("Form 10-K"), for the fiscal year ended December 31, 2025, filed with the SEC on February 26, 2026. Additionally, the calculation for adjusted EPS, on which achievement of Company Objectives is determined also differs from our calculation of Adjusted EPS (non-GAAP), set forth in the Company's Current Report on Form 8-K, filed with the SEC on February 24, 2026.

Specifically, the revenue calculation for purposes of achievement of Company Objectives is adjusted to reflect the impact of (i) any acquisitions completed in the year and (ii) changes in foreign exchange rates. Similarly, the EPS calculation for purposes of achievement of Company Objectives is adjusted to reflect the impact of (i) any acquisitions completed in the year, (ii) changes in foreign exchange rates and (iii) investment income. The Compensation Committee has determined that these adjustments better reflect the Company's underlying business performance and the efforts of management. The impact of acquisitions are outside of the Company's ordinary business and management has no control over exchange rate fluctuations or investment income impact to the financial statements. The Compensation Committee believes these adjustments are in the best interest of shareholders, as these adjustments help to normalize achievement metrics for extraordinary factors and factors outside of management's control, which may have a favorable or unfavorable impact on Company Objectives.

For the 2025 Plan, the Company set for each NEO the following Target Award and weighting for Company Objectives and Individual Performance Objectives:

Individual Annual Cash Incentive Targets(1)

Achievement of 2025 Company Objectives

The following table summarizes our target performance and actual achievement in accordance with the performance measures as described above:

Achievement of Individual Performance Objectives

In addition to the Company Objectives, NEOs, with the exception of Mr. Loeillot, have a component of their annual cash incentive compensation determined based upon achievement of Individual Performance Objectives. Our CEO evaluates the actual performance of the other executive officers against these objectives and submits such evaluations to the Compensation Committee. The ultimate determination of achievement of the Individual Performance Objectives is at the sole discretion of the Compensation Committee. The performance assessment for the Individual Performance Objectives is not calculated on a line-item basis, but rather

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represents an overall assessment of how the NEO contributed to the success of the Company through and within his or her area of responsibility. The Individual Performance Objectives are designed to be challenging to achieve at 100%. The Compensation Committee has assessed the attainment of these objectives by Messrs. Garland, Bylund, Kuriyel and Douglass for 2025 and determined achievement of the Individual Performance Objectives for such NEOs as described below.

As the Company's CFO, Mr. Garland, is responsible for the Company's internal systems and financial controls. Specifically, the CFO's Individual Performance Objectives for 2025 included scaling the Company's global Financial and Information Technology organizations, which included continuous improvements in the Company's financial closing and internal controls processes and the continued expansion and improvement of both management and external reporting capabilities to enhance business decision making and improve transparency and visibility of financial performance. The overall evaluation of achievement of these factors involves both quantitative and qualitative analysis. The CEO evaluated Mr. Garland's actual performance against his Individual Performance Objectives, in light of his contributions detailed above, and submitted such evaluation to the Compensation Committee. The Compensation Committee determined that the aggregate achievement of the Individual Performance Objectives for Mr. Garland was 105%.

Mr. Bylund, the Company's COO, oversees all operations on a global basis. Mr. Bylund's Individual Performance Objectives for 2025 included driving process efficiencies across the organization through our Repligen Performance System, rightsizing the organizations manufacturing footprint, integrating acquired workflows and products and driving customer excellence through service and quality. The overall evaluation of achievement of these factors involves both quantitative and qualitative analysis. The CEO evaluated Mr. Bylund's actual performance against his Individual Performance Objectives, in light of his contributions detailed above, and submitted such evaluation to the Compensation Committee. The Compensation Committee determined that the aggregate achievement of the Individual Performance Objectives for Mr. Bylund was 105%.

Mr. Kuriyel, the Company's Senior Vice President, R&D, is responsible for leading and overseeing the Company's R&D and partnering activities to enhance our portfolio of products and services. Mr. Kuriyel's Individual Performance Objectives for 2025 included developing and launching new products, evaluating and investing in new value-added, differentiated technology for the Company, and scaling the R&D organization to align with the needs of the business. The overall evaluation of achievement of these factors involves both quantitative and qualitative analysis. The CEO evaluated Mr. Kuriyel's actual performance against his Individual Performance Objectives, in light of his contributions detailed above, and submitted such evaluation to the Compensation Committee. The Compensation Committee determined that the aggregate achievement of the Individual Performance Objectives for Mr. Kuriyel was 105%.

Mr. Douglass, the Company's Senior Vice President and CPO, leads the organization's product management function and oversees the strategic, operational, and financial performance of its business units. This role drives product strategy, commercial execution, and business unit success while collaborating closely with corporate functions ensuring our product portfolio delivers exceptional value to customers and stakeholders. Mr. Douglass's individual performance objectives in 2025 included accelerating growth through a transformed customer experience, implementing an operating model centered on business unit teams and developing a strategy and new product introduction roadmap for the proteins business. The overall evaluation of achievement of these factors involves both quantitative and qualitative analysis. The CEO evaluated Mr. Douglass's actual performance against his Individual Performance Objectives, in light of his contributions detailed above, and submitted such evaluation to the Compensation Committee. The Compensation Committee determined that the aggregate achievement of the Individual Performance Objectives for Mr. Douglass was 105%.

The following payouts under the cash incentive were earned by our NEOs in 2025:

EQUITY INCENTIVE COMPENSATION

The Compensation Committee believes that equity incentives in the form of stock options, restricted stock units subject to time-based vesting ("RSUs") and performance-based restricted stock units ("PSUs") are effective vehicles for long-term compensation. Equity incentives align individual and team performance with the achievement of the Company's strategic and financial goals, long-term value creation, and shareholders' interests. PSUs reward executive officers only if the Company meets certain specified financial and/or operational metrics. Stock options reward executive officers only if the stock price increases from the date of grant

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over time. RSUs are impacted by all stock price changes, so the value to the executive officers is affected by both increases and decreases in stock price from the market price at the date of grant.

For 2025, the Compensation Committee considered a number of factors in determining how much, if any, equity incentive compensation to grant to the executive officers, including:

Based on its evaluation of the foregoing factors, the Compensation Committee determined that each continuing NEO's annual 2025 target LTI value would be allocated among three equity vehicles as shown in the graph below:

2025 Equity Grants

In 2025, the Compensation Committee granted the following long-term incentive compensation awards to each of the NEOs:

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The 2025 Equity Grants consist of the following:

Repligen isa high-growth, acquisitive, innovation-driven company, the Compensation Committee believes that revenue growth and Adjusted ROIC are metrics that reflect business performance and that create shareholder value. Linear interpolation is applied to determine the percentage of PSUs that vest and are earned where performance falls between the threshold, target, and maximum goals. For any portion of the PSUs to be earned and to vest, threshold performance must be achieved with respect to the relevant performance measure. 50% of the target award is earned for threshold performance and 200% of the target award is earned for maximum performance.

The PSUs that vest at the conclusion of the performance period are settled in a like number of shares of our Common Stock.

Looking Ahead to 2026

The Compensation Committee has made several decisions relating to the long-term equity incentive beginning with awards granted in fiscal 2026 fiscal, including:

The PSUs granted to Mr. Douglass on December 31, 2025 are subject to the performance conditions described above. With respect to the portion of the PSUs based on the rTSR component, we have selected a the Life Science Tools & Services companies in the Russell 1000 Index as the TSR peer group, and performance will be measured over a three-year performance period from January 1, 2026 to December 31, 2028. These PSUs will vest based on achievement of rTSR at the 25th, 50th and 75th percentile rankings of the peer group, representing threshold, target and maximum achievement, respectively. If achievement is below the 25th percentile, no payout is awarded. 50% of the target award is earned for threshold performance and 200% of the target award is earned for maximum performance. Straight-line interpolation will be applied if performance is between the threshold and target, and target and maximum goals.

Long-term Equity Incentive Payout for NEOs for 2025

In 2023, the Compensation Committee granted PSU awards to Messrs. Bylund and Kuriyel, subject to a three-year performance period ending December 31, 2025. At the time of this long-term equity incentive award, Messrs. Loeillot, Garland and Douglass were

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not employed by the Company. At the end of the three-year performance period, these PSU award metrics were not attained and thus the 2023 PSUs were forfeited in their entirety. For more information on these PSUs see the section titled "Proxy Statement Summary - Long-term Equity Incentive payout for NEOs for 2025" on page 6.

POLICIES AND PRACTICES RELATED TO THE GRANTS OF CERTAIN EQUITY AWARDS

In October 2023, the Compensation Committee adopted the Repligen Corporation Compensation Recovery Policy (the "Clawback Policy") which provides that if the Company is required to prepare an accounting restatement due to the Company's material non-compliance with any financial reporting requirement we are required to recoup (subject to certain limited exceptions described in the Clawback Policy) any cash or equity incentive compensation received by any current or former executive officer in the three years prior to the date we are required to restate our financial statements that is in excess of the amount that would have been received based on the restated financial statements. In addition, under the Clawback Policy, in the event that we are required to restate our financial statements due to material noncompliance with any financial reporting requirement under securities laws, we may recover (i) any cash or equity incentive compensation received by any other current or former employee of the Company in the three years prior to the date we are required to restate our financial statements that is in excess of the amount that would have been received based on the restated financial statements if we determine that the employee committed certain acts or omissions that materially contributed to the circumstances requiring the restatement and (ii) up to 100% of the cash and equity incentive compensation received by any current or former employee of the Company in the three years prior to the date we are required to restate our financial statements if we determine that the employee committed certain acts or omissions that materially contributed to the circumstances requiring the restatement. A copy of the Clawback Policy is included as Exhibit 97.1 to our Form 10-K.

OTHER COMPENSATION

All full-time employees, including the executive officers, are eligible to participate in the Company's health and welfare benefit programs, including medical, dental and vision care coverage, disability and life insurance and the Company's 401(k) plan. Under the 401(k) plan, the Company matches 50% of the first 6% of eligible compensation contributed by employees.

TAX AND ACCOUNTING CONSIDERATIONS

We have not provided or agreed to provide any of the Company's executive officers or directors with a gross-up or other reimbursement for tax amounts they might pay pursuant to Section 4999 or Section 409A of the Internal Revenue Code of 1986, as amended (the "Code"). Sections 280G and 4999 of the Code provide that executive officers and directors who hold significant shareholder interests and certain other service providers could be subject to significant additional taxes if they receive payments or benefits in connection with a change in control of the Company that exceed certain limits, and that we or our successor could lose a deduction on the amounts subject to the additional tax. Section 409A also imposes additional significant taxes on the individual in the event that an employee, director or service provider receives "deferred compensation" that is not exempt from or does not meet the requirements of Section 409A.

For the Company's financial statements, cash compensation, such as salary and bonus, is expensed. For income tax returns, cash compensation is generally deductible except as set forth below. For equity-based compensation, we expense the fair value of such grants over the requisite service period.

Generally, Section 162(m) of the Code disallows a federal income tax deduction for public corporations of remuneration in excess of $1 million paid for any fiscal year to a "covered employee" of the Company.

The Compensation Committee believes that shareholder interests are best served if the Compensation Committee retains maximum flexibility to design executive compensation programs that meet stated business objectives. For these reasons, the Compensation Committee, while considering tax deductibility as a factor in determining executive compensation, may not limit such compensation to those levels that will be deductible, particularly in light of the expansion of the covered employee group and the elimination of the exception for performance-based compensation under Section 162(m).

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COMPENSATION RISK ASSESSMENT

The Compensation Committee not only considers and evaluates risks related to the Company's cash and equity-based compensation programs and practices, but also evaluates whether the Company's compensation plans encourage participants to take excessive risks that are reasonably likely to have a material adverse effect on the Company. Consistent with SEC disclosure requirements, the Compensation Committee has worked with management to assess compensation policies and practices for Company employees and has concluded that such policies and practices do not create risks that are reasonably likely to have a material adverse effect on the Company.

EXECUTIVE COMPENSATION TABLES

Compensation Earned

The following table summarizes the compensation that we paid to, or that was earned by or granted to, each of the NEOs during the fiscal years indicated below.

2025 Summary Compensation Table