David S. Grayzel - Oct 23, 2025 Form 4 Insider Report for Q32 Bio Inc. (QTTB)

Role: Director
Signature: /s/ Eric Bell, Attorney-in-Fact
Stock symbol: QTTB
Transactions as of: Oct 23, 2025
Transactions value $: $0
Form type: 4
Date filed: 10/27/2025, 09:17 PM
Previous filing: Feb 26, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
GRAYZEL DAVID S.	Director	Q32 BIO INC., 830 WINTER STREET, WALTHAM	/s/ Eric Bell, Attorney-in-Fact	2025-10-27	0001732786

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	QTTB	Stock Option (Right to Buy)	Award	$0	+53.5K		$0.00	53.5K	Oct 23, 2025	Common Stock	53.5K	$2.80	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) October 23, 2026 or (ii) the date of the Issuer's next annual meeting of stockholders, subject to the Reporting Person's continued service on such vesting date.
F2	This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

Content

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) October 23, 2026 or (ii) the date of the Issuer's next annual meeting of stockholders, subject to the Reporting Person's continued service on such vesting date.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.