[SCHEDULE 13G/A] Repligen Corp SEC Filing

Rhea-AI Filing Summary

T. Rowe Price Associates, Inc. filed an Amendment No. 6 to Schedule 13G reporting ownership of 3,429,547 shares of Repligen Corp common stock, representing 6.1% of the class. The filing shows T. Rowe Price has sole voting power over 3,170,704 shares and sole dispositive power over 3,429,435 shares. No shared voting or dispositive power is reported.

The filer certifies the shares are held in the ordinary course of business and not for the purpose of changing or influencing control. The filing lists Maryland as the filer’s place of organization and provides issuer and filer addresses.

Positive

• Disclosed substantial stake: Reporting ownership of 3,429,547 shares (6.1%), a material, clearly quantified position.
• Sole authority reported: 3,170,704 shares with sole voting power and 3,429,435 shares with sole dispositive power, indicating clear control of voting and disposition by the filer.
• Filing classification: Submitted as a Schedule 13G/A with a certification that shares are held in the ordinary course of business, consistent with passive ownership disclosure.

Negative

• None.

Insights

Securities Analyst

TL;DR: T. Rowe Price holds a disclosed >5% passive position in RGEN with full sole voting and dispositive authority reported.

This Schedule 13G/A demonstrates that a major institutional investment adviser holds a meaningful stake (6.1%) in Repligen. The split between voting power (3,170,704) and dispositive power (3,429,435) is consistent with standard portfolio ownership where voting and disposition are exercised by the adviser. The certification that holdings are in the ordinary course of business indicates a passive intent under Rule 13d-1(b), reducing the implication of an activist intent to change control.

Corporate Governance Specialist

TL;DR: Institutional ownership above 5% is material for disclosure and governance monitoring but does not itself imply control changes.

From a governance perspective, a 6.1% stakeholder is relevant for board and shareholder engagement dynamics. The filing reports no shared powers and explicitly disclaims any intent to influence control, which aligns with Schedule 13G filing treatment rather than Schedule 13D. This filing should prompt issuer monitoring of institutional investor interactions but contains no affirmative governance action.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

REPLIGEN CORP

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

759916109

(CUSIP Number)

08/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 759916109

1

Names of Reporting Persons

T. Rowe Price Associates, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MARYLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 3,170,704.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 3,429,435.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,429,547.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: REPLIGEN CORP
(b)	Address of issuer's principal executive offices: 41 SEYON STREET, BUILDING 1, SUITE 100, WALTHAM, MA, 02453
Item 2.
(a)	Name of person filing: T. Rowe Price Associates, Inc.
(b)	Address or principal business office or, if none, residence: 1307 Point Street, Baltimore, MD 21231
(c)	Citizenship: Maryland
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 759916109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 3429547
(b)	Percent of class: 6.1 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 3170704
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 3429435
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. T. Rowe Price Associates, Inc. hereby declares and affirms that the filing of Schedule 13G shall not be construed as an admission that Price Associates is the beneficial owner of the securities referred to, which beneficial ownership is expressly denied.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

T. Rowe Price Associates, Inc.

Signature:	Ellen York
Name/Title:	Vice President
Date:	09/08/2025

FAQ

How many Repligen (RGEN) shares does T. Rowe Price Associates report owning?

The filer reports beneficial ownership of 3,429,547 shares of Repligen common stock.

What percentage of RGEN does T. Rowe Price own according to this filing?

The filing states ownership of 6.1% of Repligen's common stock.

Does T. Rowe Price have voting control over its reported RGEN shares?

Yes; the filing reports sole voting power over 3,170,704 shares and sole dispositive power over 3,429,435 shares.

Is the T. Rowe Price stake reported as passive or active?

The filer certifies the shares are held in the ordinary course of business and not for the purpose of changing or influencing control, consistent with a passive Schedule 13G filing.

When was this Schedule 13G/A signed by the filer?

The signature block shows Ellen York, Vice President, dated 09/08/2025.