Septerna (SEPN) CPO exercises options, then sells 70,453 shares

Rhea-AI Filing Summary

Septerna, Inc. Chief People Officer Samira Shaikhly exercised several stock options on March 2, 2026, converting 53,714, 11,638, and 5,101 option shares into common stock at exercise prices of $1.55 and $2.76 per share. She then sold a total of 70,453 common shares in open-market transactions at weighted-average prices of $27.5052 and $28.1383, under a pre-arranged Rule 10b5-1 sales plan adopted on October 31, 2025. After these trades, she directly held 793 Septerna common shares, a balance that includes shares acquired through the company’s 2024 Employee Stock Purchase Plan.

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
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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).

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^*

Shaikhly Samira

(Last) (First) (Middle)

C/O SEPTERNA, INC.

250 EAST GRAND AVENUE

(Street)

SOUTH SAN FRANCISCO CA 94080

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

3. Date of Earliest Transaction (Month/Day/Year)
03/02/2026

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

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

X	Form filed by One Reporting Person
	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		M		53,714	A	$1.55	54,507(1)	D
Common Stock	03/02/2026		M		11,638	A	$2.76	66,145	D
Common Stock	03/02/2026		M		5,101	A	$2.76	71,246	D
Common Stock	03/02/2026		S(2)		4,090	D	$27.5052(3)	67,156	D
Common Stock	03/02/2026		S(2)		66,363	D	$28.1383(4)	793	D

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)	$1.55	03/02/2026		M			53,714	(5)	03/30/2033	Common Stock	53,714	$0	15,969	D
Stock Option (Right to Buy)	$2.76	03/02/2026		M			11,638	(5)	11/11/2033	Common Stock	11,638	$0	3,460	D
Stock Option (Right to Buy)	$2.76	03/02/2026		M			5,101	(6)	03/19/2034	Common Stock	5,101	$0	5,101	D

Explanation of Responses:

1. 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).

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

3. 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.

4. 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.

5. 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.

6. 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.

	/s/ Mark A. Wilson, Attorney-in-Fact	03/04/2026
	** 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 did Septerna (SEPN) insider Samira Shaikhly report on this Form 4?

Samira Shaikhly reported exercising multiple stock options and then selling common shares in the open market. The transactions occurred on March 2, 2026, and reflect both option exercises into stock and subsequent sales, leaving her with 793 directly held Septerna shares afterward.

How many Septerna (SEPN) shares did Samira Shaikhly sell and at what prices?

She sold a total of 70,453 Septerna common shares. One sale of 4,090 shares used a weighted-average price of $27.5052, and another sale of 66,363 shares used a weighted-average price of $28.1383, with individual trades executed within stated price ranges.

What stock options did Samira Shaikhly exercise in Septerna (SEPN)?

She exercised stock options covering 53,714 shares at $1.55 per share and 11,638 and 5,101 shares at $2.76 per share. These options vest in monthly installments under schedules beginning February 1, 2024 and March 1, 2024, contingent on continued service.

Was Septerna (SEPN) insider Samira Shaikhly’s share sale under a Rule 10b5-1 plan?

Yes. The filing states the sales were effected pursuant to a Rule 10b5-1 trading plan. That plan was adopted by Samira Shaikhly on October 31, 2025, providing a pre-arranged framework for executing these stock sale transactions on March 2, 2026.

How many Septerna (SEPN) shares does Samira Shaikhly own after these transactions?

After completing the option exercises and stock sales, she directly holds 793 Septerna common shares. The filing notes this balance includes 793 shares acquired earlier through the Septerna, Inc. 2024 Employee Stock Purchase Plan in a transaction exempt under Rule 16b-3(c).

What are the vesting terms of the Septerna (SEPN) options in this Form 4?

One option had 25% of underlying shares vest on February 1, 2024, with the remainder vesting in 36 monthly installments. Another option vests 1/48th of the shares monthly starting March 1, 2024, in each case requiring continuous service to Septerna for vesting.