Pfizer discloses 2.3% Q32 Bio (QTTB) stake in amended Schedule 13G

Rhea-AI Filing Summary

Pfizer Inc. has filed an amended Schedule 13G reporting a passive minority stake in Q32 Bio Inc. Pfizer reports beneficial ownership of 277,777 shares of Q32 Bio common stock, representing 2.3% of the outstanding shares.

The ownership percentage is based on 12,304,352 Q32 Bio common shares outstanding as of November 1, 2025, as disclosed by the company. Pfizer notes that its holdings trace back to shares it previously reported in Homology Medicines, Inc., which merged into Q32 Bio with Q32 Bio as the surviving entity.

Pfizer certifies that the securities were not acquired and are not held for the purpose of changing or influencing control of Q32 Bio, confirming this is a passive investment position below the 5% threshold.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Q32 Bio Inc.

(Name of Issuer)

Common Stock par value $0.0001 per share

(Title of Class of Securities)

746964105

(CUSIP Number)

12/31/2024

(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. 746964105

1

Names of Reporting Persons

Pfizer Inc. (IRS Identification No.: 13-5315170)

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 277,777.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 277,777.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

277,777.00

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)

2.3 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Percent of class outstanding represented by the amount in row (11) is based on a total of 12,304,352 shares of common stock outstanding as of November 1, 2025, as reported on the cover of the Issuer's quarterly report on Form 10-Q for the quarterly period ended September 30, 2025 filed by the Issuer with the U.S. Securities and Exchange Commission on November 13, 2025. The Reporting Person previously reported holding shares in Homology Medicines, Inc. The Issuer reported that, effective as of March 25, 2024, Homology Medicines, Inc. completed a merger with and into the Issuer (previously named Q32 Bio Inc.), with the Issuer continuing as the surviving entity.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Q32 Bio Inc.
(b)	Address of issuer's principal executive offices: 830 Winter Street, Waltham, Massachusetts, 2451
Item 2.
(a)	Name of person filing: Pfizer Inc.
(b)	Address or principal business office or, if none, residence: 66 Hudson Boulevard East, New York, NY10001-2192
(c)	Citizenship: Delaware
(d)	Title of class of securities: Common Stock par value $0.0001 per share
(e)	CUSIP No.: 746964105
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: See the respective responses of the Reporting Persons to Item 9 on the attached cover pages.
(b)	Percent of class: See the respective responses of the Reporting Persons to Item 11 on the attached cover pages.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See the respective responses of the Reporting Persons to Item 5 on the attached cover pages.
	(ii) Shared power to vote or to direct the vote: See the respective responses of the Reporting Persons to Item 6 on the attached cover pages.
	(iii) Sole power to dispose or to direct the disposition of: See the respective responses of the Reporting Persons to Item 7 on the attached cover pages.
	(iv) Shared power to dispose or to direct the disposition of: See the respective responses of the Reporting Persons to Item 8 on the attached cover pages.
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.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. 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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Not applicable
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. Not applicable
Item 9.	Notice of Dissolution of Group.
	Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5. 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 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.

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.

Pfizer Inc. (IRS Identification No.: 13-5315170)

Signature:	/s/ Madelyn D. Purcell
Name/Title:	Madelyn D. Purcell/Assistant Secretary
Date:	02/13/2026

FAQ

What percentage of Q32 Bio Inc. (QTTB) does Pfizer Inc. report owning?

Pfizer reports owning 2.3% of Q32 Bio’s common stock. This percentage is calculated against 12,304,352 shares outstanding as of November 1, 2025, as disclosed in Q32 Bio’s Form 10-Q.

How many Q32 Bio (QTTB) shares does Pfizer Inc. beneficially own?

Pfizer Inc. reports beneficial ownership of 277,777 Q32 Bio common shares. The filing also notes Pfizer has sole voting and sole dispositive power over this entire block, with no shared voting or dispositive authority reported.

Is Pfizer’s Q32 Bio (QTTB) stake considered a passive investment?

Yes, Pfizer certifies that its Q32 Bio shares were not acquired to change or influence control. The Schedule 13G certification states the holdings are not connected with any control-seeking transaction, indicating a passive investment intent under applicable SEC rules.

How was Pfizer’s stake in Q32 Bio (QTTB) originally obtained?

Pfizer previously reported holdings in Homology Medicines, Inc. Q32 Bio later reported that Homology Medicines merged into Q32 Bio, with Q32 Bio as the surviving company, effectively converting Pfizer’s prior Homology stake into Q32 Bio shares.

Why does Pfizer’s Q32 Bio (QTTB) filing reference less than 5% ownership?

The filing includes an item for ownership of 5% or less, reflecting that Pfizer’s 2.3% stake is below the 5% threshold. Below this level, the position is considered a small minority holding rather than a large, potentially controlling stake.

What share count did Pfizer use to calculate its Q32 Bio (QTTB) ownership percentage?

Pfizer’s 2.3% ownership figure is based on 12,304,352 Q32 Bio common shares outstanding. This total outstanding share count comes from Q32 Bio’s Form 10-Q cover page for the quarter ended September 30, 2025.