Carlyle group reports 4.1% stake in Q32 Bio

Q32 Bio Inc. Schedule 13G/A shows that a group of Carlyle-related entities reports shared beneficial ownership of 691,735 shares of Common Stock, representing 4.1% of the class as of June 18, 2026.

Rhea-AI Filing Summary

Q32 Bio Inc. Schedule 13G/A shows that a group of Carlyle-related entities reports shared beneficial ownership of 691,735 shares of Common Stock, representing 4.1% of the class as of June 18, 2026. The filing cites 16,956,415 shares outstanding as disclosed in the issuer's Form 10-Q filed May 5, 2026. The reporting chain traces record ownership to Abingworth Bioventures VII LP with investment/dispositive authority delegated to Abingworth LLP; multiple Carlyle entities disclaim direct beneficial ownership while the cover pages report shared voting and dispositive power.

Insights

Institutional Ownership Analyst

Large investment firms report a passive, sub-5% stake in Q32 Bio.

The filing lists 691,735 shares (4.1%) beneficially owned as of June 18, 2026, based on 16,956,415 shares outstanding. Ownership is reported through a nested Carlyle/Abingworth structure with shared voting and dispositive power indicated.

Because the position is under 5% and filed on Schedule 13G/A, it is presented as passive ownership. Subsequent filings would show any change in status or percentage.

Corporate Governance Specialist

Complex entity chain yields shared control disclosures rather than direct ownership claims.

The statement discloses delegated investment and dispositive authority from Abingworth Bioventures VII LP to Abingworth LLP and lists multiple Carlyle affiliates as reporting persons sharing power over the same 691,735 shares.

Signatures by authorized signatories are included; follow-on Schedule 13D/G amendments would be required if the holder moves from passive to active intent.

Key Figures

Beneficial ownership: 691,735 shares Percent of class: 4.1% Shares outstanding: 16,956,415 shares

3 metrics

Beneficial ownership 691,735 shares Beneficially owned as of June 18, 2026

Percent of class 4.1% Calculated from outstanding shares disclosed in issuer Form 10-Q

Shares outstanding 16,956,415 shares Issuer's Form 10-Q filed May 5, 2026 (used as denominator)

Key Terms

beneficial ownership, shared dispositive power, Schedule 13G/A

3 terms

beneficial ownership regulatory

"The information contained on the cover pages to this is incorporated by reference"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

shared dispositive power regulatory

"Shared power to dispose or to direct the disposition of: 691,735"

Schedule 13G/A regulatory

"Item 1. (a) Name of issuer: Q32 Bio Inc."

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Carlyle report in QTTB (Q32 Bio) in this filing?

The filing reports shared beneficial ownership of 691,735 shares, equal to 4.1% of the class as of June 18, 2026. That percentage is calculated using 16,956,415 shares outstanding cited from the issuer's Form 10-Q filed May 5, 2026.

Who is the record holder of the shares reported in the QTTB filing?

The filing states that Abingworth Bioventures VII LP is the record holder of the reported shares. Investment and dispositive power over those shares is delegated to Abingworth LLP, which is reflected in the shared power disclosures.

Does the Schedule 13G/A indicate active control or passive ownership for QTTB?

This Schedule 13G/A presents the position as passive ownership under Section 13(g) conventions. The report lists shared voting and dispositive power but does not assert an intent to influence control; a conversion to an active stance would require an amended filing.

How was the 4.1% ownership percentage in QTTB calculated?

The percentage is shown as 4.1% based on 691,735 shares beneficially owned divided by the issuer's disclosed 16,956,415 shares outstanding as reported in the issuer's Form 10-Q filed May 5, 2026.

Which entities signed the QTTB Schedule 13G/A on behalf of the reporting group?

Authorized signatories include Anne K. Frederick and Emma O'Reilly signing for multiple Carlyle and Abingworth entities. The filing includes a Joint Filing Agreement (Exhibit 99) referenced as previously filed.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 07/06/2026 - 07:20 PM Learn about SEC filing dates

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)

06/30/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

The Carlyle Group 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Carlyle Holdings I GP 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Carlyle Holdings I GP Sub L.L.C.

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Limited Liability Company

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Carlyle Holdings I L.P.

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

CG Subsidiary Holdings L.L.C.

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Limited Liability Company

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

TC Group, L.L.C.

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Limited Liability Company

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Carlyle Investment Management L.L.C.

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Limited Liability Company

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Carlyle Genesis UK LLC

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 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: Limited Liability Company

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Abingworth LLP

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

UNITED KINGDOM

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 746964105

1

Names of Reporting Persons

Abingworth Bioventures VII LP

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

UNITED KINGDOM

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 691,735.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 691,735.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

691,735.00

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)

4.1 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Q32 Bio Inc.
(b)	Address of issuer's principal executive offices: 830 Winter Street, Waltham, MA, 02451
Item 2.
(a)	Name of person filing: Each of the following is hereinafter individually referred to as a "Reporting Person" and collectively as the "Reporting Persons." This statement is filed on behalf of: The Carlyle Group Inc. Carlyle Holdings I GP Inc. Carlyle Holdings I GP Sub L.L.C. Carlyle Holdings I L.P. CG Subsidiary Holdings L.L.C. TC Group, L.L.C. Carlyle Investment Management L.L.C. Carlyle Genesis UK LLC Abingworth LLP Abingworth Bioventures VII LP
(b)	Address or principal business office or, if none, residence: The principal business address of each of Abingworth LLP and Abingworth Bioventures VII LP is 38 Jermyn Street, London, SW1Y 6DN, England, United Kingdom. The principal business address of each of the other Reporting Persons is c/o The Carlyle Group, 1001 Pennsylvania Ave. NW, Suite 220 South, Washington, DC 20004-2505.
(c)	Citizenship: Each of Abingworth LLP and Abingworth Bioventures VII LP is organized under the laws of England and Wales. Each of the other Reporting Persons is organized under the laws of the State of 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: The information contained on the cover pages to this Schedule 13G is incorporated by reference into this Item 4. The ownership information presented below represents beneficial ownership of Common Stock of the Issuer as of June 18, 2026, based upon 16,956,415 shares of Common Stock outstanding, as disclosed in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on May 5, 2026. Abingworth Bioventures VII LP is the record holder of the shares of Common Stock reported herein. The Carlyle Group Inc., which is a publicly traded entity listed on Nasdaq, is the sole shareholder of Carlyle Holdings I GP Inc., which is the sole member of Carlyle Holdings I GP Sub L.L.C., which is the general partner of Carlyle Holdings I L.P., which, with respect to the securities reported herein, is the managing member of CG Subsidiary Holdings L.L.C., which is the managing member of TC Group, L.L.C., which is the managing member of Carlyle Investment Management L.L.C., which is the sole member of Carlyle Genesis UK LLC, which is the principal member of Abingworth LLP. Abingworth Bioventures VII LP has delegated to Abingworth LLP all investment and dispositive power over the securities held of record by them. Accordingly, each of the foregoing entities may be deemed to share beneficial ownership of the securities held of record by Abingworth Bioventures VII LP, but each disclaims beneficial ownership of such securities.
(b)	Percent of class: 4.1%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 691,735
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 691,735
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 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.

The Carlyle Group Inc.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Corporate Secretary
Date:	07/06/2026

Carlyle Holdings I GP Inc.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

Carlyle Holdings I GP Sub L.L.C.

Signature:	By: Carlyle Holdings I GP Inc., its sole member, /s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

Carlyle Holdings I L.P.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

CG Subsidiary Holdings L.L.C.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

TC Group, L.L.C.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

Carlyle Investment Management L.L.C.

Signature:	/s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

Carlyle Genesis UK LLC

Signature:	By: Carlyle Investment Management L.L.C., its sole member, /s/ Anne K. Frederick
Name/Title:	Anne K. Frederick, Managing Director
Date:	07/06/2026

Abingworth LLP

Signature:	/s/ Emma O'Reilly
Name/Title:	Emma O'Reilly. Authorized Signatory
Date:	07/06/2026

Abingworth Bioventures VII LP

Signature:	/s/ Emma O'Reilly
Name/Title:	Emma O'Reilly. Authorized Signatory
Date:	07/06/2026

Exhibit Information

Exhibit 99: Joint Filing Agreement (previously filed)