Septerna, Inc. Common Stock (SEPN) Form 4 Change in insider ownership

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

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

1. Name and Address of Reporting Person^*

Third Rock Ventures VI, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Septerna, Inc. [ SEPN ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
02/20/2025

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	02/20/2025		P		612,674	A	$5.92(1)	3,765,130	D(2)(5)
Common Stock	02/21/2025		P		427,668	A	$5.94(3)	4,192,798	D(2)(5)
Common Stock								6,215,591	I	See Footnotes(4)(5)

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

1. Name and Address of Reporting Person^*

Third Rock Ventures VI, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures V, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP V, LP

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

TRV GP V, LLC

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP VI, L.P.

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

TRV GP VI, LLC

(Last) (First) (Middle)

C/O THIRD ROCK VENTURES, LLC

201 BROOKLINE AVE, SUITE 1401

(Street)

BOSTON MA 02215

(City) (State) (Zip)

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $5.39 to $6.00, inclusive. The Reporting Persons undertake 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 purchased at each separate price at which the transactions were effected.

2. The shares are held directly by Third Rock Ventures VI, L.P. ("TRV VI"). The general partner of TRV VI is Third Rock Ventures GP VI, L.P. ("TRV GP VI"). The general partner of TRV GP VI is TRV GP VI, LLC ("TRV GP VI LLC"). Each of TRV GP VI, and TRV GP VI LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

3. The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $5.67 to $6.00, inclusive. The Reporting Persons undertake 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 purchased at each separate price at which the transactions were effected.

4. The shares are held directly by Third Rock Ventures V, L.P. ("TRV V"). The general partner of TRV V is Third Rock Ventures GP V, L.P. ("TRV GP V"). The general partner of TRV GP V is TRV GP V, LLC ("TRV GP V LLC"). Each of TRV GP V, and TRV GP V LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

5. Each of Reporting Persons disclaims the existence of a Section 13(d) "group" as between the TRV V related parties and the TRV VI related parties and this report shall not be deemed an admission that any of such parties is or may be part of such a group with any of the other parties.

	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P., general partner of Third Rock Ventures V, L.P.	02/24/2025
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P.	02/24/2025
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC	02/24/2025
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP VI, LLC, general partner of Third Rock Ventures GP VI, L.P., general partner of Third Rock Ventures VI, L.P.	02/24/2025
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP VI, LLC, general partner of Third Rock Ventures GP VI, L.P.	02/24/2025
	/s/ Kevin Gillis, Chief Operating Officer of TRV GP VI, LLC	02/24/2025
	** 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).
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