Septerna, Inc. — Director's Dealing 2026

Mar 4, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Septerna, Inc. (SEPN)
CIK: 0001984086
Period of Report: 2026-03-02

Reporting Person: Shaikhly Samira (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-03-02	Common Stock	M	53714	$1.55	Acquired	54507	Direct
2026-03-02	Common Stock	M	11638	$2.76	Acquired	66145	Direct
2026-03-02	Common Stock	M	5101	$2.76	Acquired	71246	Direct
2026-03-02	Common Stock	S	4090	$27.5052	Disposed	67156	Direct
2026-03-02	Common Stock	S	66363	$28.1383	Disposed	793	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-03-02	Stock Option (Right to Buy)	$1.55	M	53714	Disposed	2033-03-30	Common Stock (53714)	Direct
2026-03-02	Stock Option (Right to Buy)	$2.76	M	11638	Disposed	2033-11-11	Common Stock (11638)	Direct
2026-03-02	Stock Option (Right to Buy)	$2.76	M	5101	Disposed	2034-03-19	Common Stock (5101)	Direct

Footnotes

F1: Includes 793 shares acquired under the Septerna, Inc. 2024 Employee Stock Purchase Plan on October 31, 2025 in a transaction that was exempt under Rule 16b-3(c).

F2: This transaction was effected pursuant to a Rule 10b5-1 sales plan adopted by the Reporting Person on October 31, 2025.

F3: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $26.90 to $27.89. 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 purchased at each separate price within the range.

F4: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $27.90 to $28.70. 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 purchased at each separate price within the range.

F5: 25% of the shares underlying this option vested on February 1, 2024, with the remainder vesting in thirty-six substantially equal monthly installments thereafter, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

F6: 1/48th of the shares subject to such option 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.