Generate Biomedicines director sells 1,000 shares

Director Frances Arnold reports a small planned sale of GENB shares while retaining sizeable direct and trust-related holdings.

Rhea-AI Filing Summary

Generate Biomedicines, Inc. (GENB) director Frances Arnold reported a sale of 1,000 shares of common stock on September 1, 2026 at a weighted average price of $16.002 per share, effected under a Rule 10b5-1 trading plan adopted on March 13, 2026. After this sale, she holds 231,472 shares directly and an additional 232,472 shares are held indirectly by The Frances Arnold 2010 Irrevocable Trust, for which she disclaims beneficial ownership except to the extent of any pecuniary interest.

Insider Trade Summary 10b5-1

Net Seller: 1,000 shares

Net Sell 2 txns

Insider ARNOLD FRANCES

Role Director

Sold 1,000 shs ($16K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	1,000	$16.002	$16K
holding	Common Stock F3	--	--	--

Holdings After Transaction: Common Stock — 231,472 shares (Direct); Common Stock — 232,472 shares (Indirect, By The Frances Arnold 2010 Irrevocable Trust)

Footnotes (3)

1. F1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 13, 2026.
2. F2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $16.00 to $16.01 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
3. F3. The Reporting Person disclaims beneficial ownership of such shares for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of her pecuniary interest therein, if any. This report shall not be deemed an admission that she is a beneficial owner of such shares for the purpose of Section 16 of the Exchange Act, or for any other purpose.

Key Figures

Shares sold: 1,000 shares Weighted average sale price: $16.002 per share Sale price range: $16.00–$16.01 per share +3 more

6 metrics

Shares sold 1,000 shares Common Stock sale on September 1, 2026

Weighted average sale price $16.002 per share Sale of 1,000 shares on September 1, 2026

Sale price range $16.00–$16.01 per share Multiple transactions comprising the 1,000-share sale

Direct holdings after transaction 231,472 shares Common Stock held directly by Frances Arnold after the sale

Indirect holdings via trust 232,472 shares Common Stock held by The Frances Arnold 2010 Irrevocable Trust

Rule 10b5-1 plan adoption date March 13, 2026 Trading plan under which the September 1, 2026 sale was effected

Key Terms

Rule 10b5-1 trading plan, weighted average price, beneficial ownership, pecuniary interest, +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

beneficial ownership regulatory

"The Reporting Person disclaims beneficial ownership of such shares"

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.

pecuniary interest financial

"except to the extent of her pecuniary interest therein, if any."

indirect ownership financial

"indirectly by The Frances Arnold 2010 Irrevocable Trust"

FAQ

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

What insider transaction did GENB director Frances Arnold report?

Frances Arnold reported a sale of 1,000 shares of Generate Biomedicines common stock on September 1, 2026 at a weighted average price of $16.002 per share, with trades occurring between $16.00 and $16.01 per share.

Was the GENB stock sale by Frances Arnold under a Rule 10b5-1 plan?

Yes. The filing states the transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by Frances Arnold on March 13, 2026, indicating the trades were pre-arranged under that plan.

How many GENB shares does Frances Arnold hold directly after this Form 4?

After the reported sale, Frances Arnold holds 231,472 shares of Generate Biomedicines common stock directly, as shown in the post-transaction holdings column for the non-derivative securities.

What are Frances Arnold’s indirect holdings of GENB shares?

An additional 232,472 shares of Generate Biomedicines common stock are held indirectly by The Frances Arnold 2010 Irrevocable Trust. She disclaims beneficial ownership of these shares except to the extent of any pecuniary interest.

What price range were the GENB shares sold for in this transaction?

The shares were sold in multiple transactions at prices ranging from $16.00 to $16.01 per share, with a reported weighted average price of $16.002 per share, as described in the footnotes.

How many total GENB shares did Frances Arnold sell in this Form 4?

The Form 4 reports that Frances Arnold sold 1,000 shares of Generate Biomedicines common stock in this transaction, with no additional purchases or sales disclosed in the same filing.

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

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Available on EDGAR 09/03/2026 - 04:07 PM EDT Accepted by SEC EDGAR 09/03/2026 - 04:05 PM EDT Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ARNOLD FRANCES

(Last) (First) (Middle)

GENERATE BIOMEDICINES, INC.

101 SOUTH STREET, SUITE 900

(Street)

SOMERVILLE MASSACHUSETTS 02143

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Generate Biomedicines, Inc. [ GENB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/01/2026		S(1)		1,000	D	$16.002(2)	231,472	D
Common Stock								232,472	I	By The Frances Arnold 2010 Irrevocable Trust(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 13, 2026.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $16.00 to $16.01 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. The Reporting Person disclaims beneficial ownership of such shares for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of her pecuniary interest therein, if any. This report shall not be deemed an admission that she is a beneficial owner of such shares for the purpose of Section 16 of the Exchange Act, or for any other purpose.

	/s/ Michael Wolf, Attorney-in-Fact	09/03/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)