STOCK TITAN

Flagship funds boost Generate Biomedicines (GENB) stake with IPO conversions, buys

Filing Impact
(Very High)
Filing Sentiment
(Very Positive)
Form Type
4

Rhea-AI Filing Summary

Generate Biomedicines, Inc. reported multiple insider-related transactions involving funds affiliated with Flagship Pioneering. On March 2, 2026, shares of Series A, B and C preferred stock held by these funds automatically converted into common stock on a one-for-1.5190 basis upon the closing of the company’s initial public offering. On the same date, Flagship Pioneering Fund VII, L.P., FPN II, L.P. and Pioneering Medicines 02, LLC each bought 1,562,500 shares of common stock at $16 per share in open-market or private transactions, for a total of 4,687,500 shares purchased. Separately, on February 26, 2026, Noubar Afeyan received a grant of 29,561 stock options that vest in full on February 19, 2027, subject to continued service.

Positive

  • None.

Negative

  • None.
Insider AFEYAN NOUBAR, Flagship VentureLabs VI LLC, Flagship Pioneering Fund VI, L.P., Flagship Pioneering Fund VII, L.P., Nutritional Health LTP Fund, L.P., Flagship Pioneering Special Opportunities Fund II, L.P., FPN II, L.P.
Role Director, 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner
Bought 4,687,500 shs ($75.00M)
Type Security Shares Price Value
Conversion Series A Preferred Stock 18,483,785 $0.00 --
Conversion Series A Preferred Stock 17,016,215 $0.00 --
Conversion Series A Preferred Stock 1,500,000 $0.00 --
Conversion Series B Preferred Stock 843,881 $0.00 --
Conversion Series B Preferred Stock 1,265,822 $0.00 --
Conversion Series B Preferred Stock 2,953,586 $0.00 --
Conversion Series B Preferred Stock 2,109,704 $0.00 --
Conversion Series C Preferred Stock 2,531,644 $0.00 --
Conversion Series C Preferred Stock 1,265,822 $0.00 --
Conversion Series C Preferred Stock 2,109,704 $0.00 --
Conversion Common Stock 12,723,940 $0.00 --
Conversion Common Stock 13,702,224 $0.00 --
Conversion Common Stock 987,491 $0.00 --
Conversion Common Stock 2,777,752 $0.00 --
Conversion Common Stock 2,777,752 $0.00 --
Purchase Common Stock 1,562,500 $16.00 $25.00M
Purchase Common Stock 1,562,500 $16.00 $25.00M
Purchase Common Stock 1,562,500 $16.00 $25.00M
Grant/Award Stock Option (Right to Buy) 29,561 $0.00 --
holding Common Stock -- -- --
Holdings After Transaction: Series A Preferred Stock — 0 shares (Indirect, By Flagship Pioneering Fund VI, L.P.); Series B Preferred Stock — 0 shares (Indirect, By Flagship Pioneering Fund VI, L.P.); Series C Preferred Stock — 0 shares (Indirect, By Flagship Pioneering Fund VII, L.P.); Common Stock — 12,723,940 shares (Indirect, By Flagship Pioneering Fund VI, L.P.); Stock Option (Right to Buy) — 29,561 shares (Direct)
Footnotes (1)
  1. Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") automatically converted into shares of the Issuer's Common Stock on a one-for-1.5190 basis upon the closing of the Issuer's initial public offering on March 2, 2026. The Preferred Stock had no expiration date. Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Securities held by Nutritional Health LTP Fund, L.P. ("Nutritional LTP"). Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering is the manager of Nutritional LTP GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Securities held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering is the manager of Flagship Opportunities Fund II GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Securities held by Pioneering Medicine 02, LLC ("PM02"). Charles R. Carelli, Jr., Chief Financial Officer of Flagship Pioneering, is the sole manager of PM02, and Flagship Fund VII is its majority equity holder. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. Securities held by Flagship VentureLabs VI LLC ("VentureLabs VI"). Flagship VentureLabs VI Manager LLC ("VentureLabs VI Manager") is the manager of VentureLabs VI. Flagship Pioneering is the manager of VentureLabs VI Manager. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. The shares underlying this option shall vest in full on February 19, 2027, subject to the Reporting Person's continued service on such vesting date.
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).
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*
AFEYAN NOUBAR

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)
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 X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
02/26/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X Form filed by More than One Reporting Person
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 03/02/2026 C 12,723,940 A (1) 12,723,940 I By Flagship Pioneering Fund VI, L.P.(2)
Common Stock 03/02/2026 C 13,702,224 A (1) 13,702,224 I By Flagship Pioneering Fund VII, L.P.(3)
Common Stock 03/02/2026 C 987,491 A (1) 987,491 I By Nutritional Health LTP Fund, L.P.(4)
Common Stock 03/02/2026 C 2,777,752 A (1) 2,777,752 I By Flagship Pioneering Special Opportunities Fund II, L.P.(5)
Common Stock 03/02/2026 C 2,777,752 A (1) 2,777,752 I By FPN II, L.P.(6)
Common Stock 03/02/2026 P 1,562,500 A $16 15,264,724 I By Flagship Pioneering Fund VII, L.P.(3)
Common Stock 03/02/2026 P 1,562,500 A $16 4,340,252 I By FPN II, L.P.(6)
Common Stock 03/02/2026 P 1,562,500 A $16 1,562,500 I By Pioneering Medicines 02, LLC(7)
Common Stock 25,016,458 I By Flagship VentureLabs VI, LLC(8)
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
Stock Option (Right to Buy) $16 02/26/2026 A 29,561 (9) 02/25/2036 Common Stock 29,561 $0 29,561 D
Series A Preferred Stock (1) 03/02/2026 C 18,483,785 (1) (1) Common Stock 12,168,390 $0 0 I By Flagship Pioneering Fund VI, L.P.(2)
Series A Preferred Stock (1) 03/02/2026 C 17,016,215 (1) (1) Common Stock 11,202,248 $0 0 I By Flagship Pioneering Fund VII, L.P.(3)
Series A Preferred Stock (1) 03/02/2026 C 1,500,000 (1) (1) Common Stock 987,491 $0 0 I By Nutritional Health LTP Fund, L.P.(4)
Series B Preferred Stock (1) 03/02/2026 C 843,881 (1) (1) Common Stock 555,550 $0 0 I By Flagship Pioneering Fund VI, L.P.(2)
Series B Preferred Stock (1) 03/02/2026 C 1,265,822 (1) (1) Common Stock 833,325 $0 0 I By Flagship Pioneering Fund VII, L.P.(3)
Series B Preferred Stock (1) 03/02/2026 C 2,953,586 (1) (1) Common Stock 1,944,427 $0 0 I By Flagship Pioneering Special Opportunities Fund II, L.P.(5)
Series B Preferred Stock (1) 03/02/2026 C 2,109,704 (1) (1) Common Stock 1,388,876 $0 0 I By FPN II, L.P.(6)
Series C Preferred Stock (1) 03/02/2026 C 2,531,644 (1) (1) Common Stock 1,666,651 $0 0 I By Flagship Pioneering Fund VII, L.P.(3)
Series C Preferred Stock (1) 03/02/2026 C 1,265,822 (1) (1) Common Stock 833,325 $0 0 I By Flagship Pioneering Special Opportunities Fund II, L.P.(5)
Series C Preferred Stock (1) 03/02/2026 C 2,109,704 (1) (1) Common Stock 1,388,876 $0 0 I By FPN II, L.P.(6)
1. Name and Address of Reporting Person*
AFEYAN NOUBAR

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
X Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Flagship VentureLabs VI LLC

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Flagship Pioneering Fund VI, L.P.

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Flagship Pioneering Fund VII, L.P.

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Nutritional Health LTP Fund, L.P.

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Flagship Pioneering Special Opportunities Fund II, L.P.

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
FPN II, L.P.

(Last) (First) (Middle)
55 CAMBRIDGE PARKWAY, SUITE 800E

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
Explanation of Responses:
1. Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
2. Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") automatically converted into shares of the Issuer's Common Stock on a one-for-1.5190 basis upon the closing of the Issuer's initial public offering on March 2, 2026. The Preferred Stock had no expiration date.
3. Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
4. Securities held by Nutritional Health LTP Fund, L.P. ("Nutritional LTP"). Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering is the manager of Nutritional LTP GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
5. Securities held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering is the manager of Flagship Opportunities Fund II GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
6. Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
7. Securities held by Pioneering Medicine 02, LLC ("PM02"). Charles R. Carelli, Jr., Chief Financial Officer of Flagship Pioneering, is the sole manager of PM02, and Flagship Fund VII is its majority equity holder. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
8. Securities held by Flagship VentureLabs VI LLC ("VentureLabs VI"). Flagship VentureLabs VI Manager LLC ("VentureLabs VI Manager") is the manager of VentureLabs VI. Flagship Pioneering is the manager of VentureLabs VI Manager. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.
9. The shares underlying this option shall vest in full on February 19, 2027, subject to the Reporting Person's continued service on such vesting date.
Remarks:
Form 1 of 2: This is the first of two Forms 4 being filed relating to the same event. The Form 4 is being split into two filings because there are more than 10 Reporting Persons in total, and the SEC's EDGAR filing system limits a single Form 4 to a maximum of 10 Reporting Persons. Each Form 4 is filed by Designated Filer Noubar Afeyan.
/s/ Noubar B. Afeyan, Ph.D. 03/02/2026
Flagship VentureLabs VI LLC, By: /s/ Noubar B. Afeyan, Ph.D., Title: Sole Member and Manager of Manager of Manager of Manager 03/02/2026
Flagship Pioneering Fund VI, L.P., By: /s/ Noubar B. Afeyan, Ph.D., Title: Sole Member and Manager of Manager of Manager of General Partner 03/02/2026
Flagship Pioneering Fund VII, L.P., By: /s/ Noubar B. Afeyan, Ph.D., Title: Sole Member and Manager of Manager of Manager of General Partner 03/02/2026
Nutritional Health LTP Fund, L.P., By: /s/ Noubar B. Afeyan, Ph.D., Title: Sole Member and Manager of Manager of Manager of General Partner 03/02/2026
Flagship Pioneering Special Opportunities Fund II, L.P., By: /s/ Noubar B. Afeyan Ph.D., Title: Sole Member and Manager of Manager of Manager of General Partner 03/02/2026
FPN II, L.P., By: /s/ Noubar B. Afeyan, Ph.D., Title: Sole Member and Manager of Manager of Manager of General Partner 03/02/2026
** 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.

FAQ

What insider transactions did Generate Biomedicines (GENB) report on March 2, 2026?

Generate Biomedicines reported that several Flagship Pioneering-affiliated funds converted Series A, B and C preferred stock into common stock and bought additional shares. These actions coincided with the company’s initial public offering and reflect portfolio-level positioning by affiliated investment vehicles.

How many GENB shares did Flagship-affiliated entities buy and at what price?

Flagship Pioneering Fund VII, FPN II and Pioneering Medicines 02, LLC each purchased 1,562,500 Generate Biomedicines common shares at $16 per share. In total, these entities acquired 4,687,500 shares through open-market or private transactions on March 2, 2026.

What happened to Generate Biomedicines’ preferred stock in connection with the IPO?

Each share of Series A, Series B and Series C preferred stock automatically converted into common stock on a one-for-1.5190 basis. This conversion occurred upon the closing of Generate Biomedicines’ initial public offering on March 2, 2026, and the preferred stock had no expiration date.

What equity award did Noubar Afeyan receive from Generate Biomedicines?

Noubar Afeyan received a grant of 29,561 stock options on February 26, 2026. These options represent a right to buy common shares and will vest in full on February 19, 2027, conditioned on his continued service through that vesting date.