Uwe Klein - 18 Aug 2025 Form 4 Insider Report for Septerna, Inc. (SEPN)

Role: SVP, Biological Sciences
Signature: /s/ Ran Xiao, Attorney-in-Fact
Issuer symbol: SEPN
Transactions as of: 18 Aug 2025
Net transactions value: +$94,367
Form type: 4
Filing time: 19 Aug 2025, 17:02:20 UTC
Previous filing: 11 Aug 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Klein Uwe	SVP, Biological Sciences	C/O SEPTERNA, INC., 250 EAST GRAND AVENUE, SOUTH SAN FRANCISCO	/s/ Ran Xiao, Attorney-in-Fact	19 Aug 2025	0002040350

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SEPN	Common Stock	Options Exercise	$28,848	+10,452		$2.76	10,452	18 Aug 2025	Direct
transaction	SEPN	Common Stock	Options Exercise	$13,621	+4,935	+47%	$2.76	15,387	18 Aug 2025	Direct
transaction	SEPN	Common Stock	Options Exercise	$51,899	+7,621	+50%	$6.81	23,008	18 Aug 2025	Direct
holding	SEPN	Common Stock						104,525	18 Aug 2025	See footnote	F1

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	SEPN	Stock Option (Right to Buy)	Options Exercise	$0	-10,452	-50%	$0.000000	10,453	18 Aug 2025	Common Stock	10,452	$2.76	Direct	F2
transaction	SEPN	Stock Option (Right to Buy)	Options Exercise	$0	-4,935	-35%	$0.000000	9,001	18 Aug 2025	Common Stock	4,935	$2.76	Direct	F3
transaction	SEPN	Stock Option (Right to Buy)	Options Exercise	$0	-7,621	-19%	$0.000000	33,027	18 Aug 2025	Common Stock	7,621	$6.81	Direct	F4

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

Explanation of Responses:

Id	Content
F1	Shares held by Klein 2024 Revocable Trust dated February 25, 2024 (the "Trust), of which the Reporting Person is a co-trustee. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.
F2	1/48th of the shares subject to such option shall vest and become exercisable in substantially equal monthly installments on each monthly anniversary of August 1, 2023, subject to the Reporting Person's continuous service to the Issuer on each such date.
F3	1/48th of the shares subject to such option shall vest and become exercisable in substantially equal monthly installments on each monthly anniversary of March 1, 2024, subject to the Reporting Person's continuous service to the Issuer on each such date.
F4	1/48th of the shares subject to such option shall vest and become exercisable in substantially equal monthly installments on each monthly anniversary of October 28, 2024, contingent upon the consummation of the Issuer's initial public offering, and subject to the Reporting Person's continuous service to the Issuer on each such date.