T. Rowe Price holds 3.1% of Generation Bio (GBIO) shares

Rhea-AI Filing Summary

T. Rowe Price Associates, Inc. filed Amendment No. 8 to a Schedule 13G reporting its beneficial ownership of 209,641 shares of Generation Bio Co.3.1% of the class as of December 31, 2025.

T. Rowe Price reports sole voting and sole dispositive power over all 209,641 shares and no shared power. The firm states the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of Generation Bio.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 8)

GENERATION BIO CO

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

37148K209

(CUSIP Number)

12/31/2025

(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. 37148K209

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 209,641.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 209,641.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

209,641.00

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)

3.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: GENERATION BIO CO
(b)	Address of issuer's principal executive offices: 301 BINNEY STREET, CAMBRIDGE, MA, 02142
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.: 37148K209
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: 209641
(b)	Percent of class: 3.1 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 209641
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 209641
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	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:	02/17/2026

FAQ

What ownership stake in GBIO does T. Rowe Price report in this Schedule 13G/A?

T. Rowe Price Associates, Inc. reports beneficial ownership of 209,641 Generation Bio shares, representing 3.1% of the common stock as of December 31, 2025. This reflects a relatively small minority position in the company’s equity.

What type of SEC filing is this for Generation Bio (GBIO)?

This is an Amendment No. 8 to Schedule 13G for Generation Bio Co.. Schedule 13G is a beneficial ownership report used mainly by institutional investors holding shares without seeking to influence control of the issuer.

Does T. Rowe Price have voting and dispositive power over its GBIO shares?

Yes. T. Rowe Price reports sole voting power over 209,641 shares and sole dispositive power over the same amount. It reports no shared voting or shared dispositive power, indicating full control over how these specific shares are voted and sold.

Is T. Rowe Price’s Generation Bio (GBIO) stake above or below 5% ownership?

T. Rowe Price states its Generation Bio holding represents 3.1% of the class, which is 5 percent or less of the company’s common stock. The filing explicitly notes ownership of 5 percent or less of a class under Item 5.

What does T. Rowe Price say about its intentions regarding control of Generation Bio?

T. Rowe Price certifies the securities were acquired and are held in the ordinary course of business and not for changing or influencing control of Generation Bio. It also states they are not held in connection with any transaction having that control-related purpose or effect.

Who signed the Schedule 13G/A filing for T. Rowe Price on Generation Bio (GBIO)?

The filing is signed by Ellen York, identified as a Vice President of T. Rowe Price Associates, Inc. The signature block includes a certification that, after reasonable inquiry, the information in the statement is true, complete, and correct as of the stated date.