[Form 4] Septerna, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Septerna, Inc. director and Senior Vice President, Biological Sciences, Uwe Klein reported multiple acquisitions of the issuer's common stock and stock options on 08/18/2025. He purchased options exercisable into 10,452, 4,935, and 7,621 shares at exercise prices of $2.76, $2.76, and $6.81 respectively, and those options underlie the reported common shares. The Form 4 shows 10,452, 4,935, and 7,621 shares were acquired at reported option prices of $2.76, $2.76, and $6.81, and following transactions Klein directly beneficially owns 23,008 shares. In addition, Klein discloses indirect ownership of 104,525 shares held by the Klein 2024 Revocable Trust (co-trustee), which he disclaims beneficial ownership of except to the extent of pecuniary interest. Vesting schedules apply to the option awards with monthly vesting and IPO-contingent vesting described in footnotes.

Positive

• Insider acquisitions reported: options and shares acquired on 08/18/2025 indicating executive equity ownership
• Clear vesting schedules disclosed, including monthly vesting and specific IPO-contingent terms
• Indirect trust holdings disclosed (104,525 shares) with appropriate disclaimer of beneficial ownership

Negative

• None.

Insights

Securities/Insider Transactions Analyst

TL;DR: Insider acquired options converting to 23,008 shares and discloses 104,525 trust-held shares; transactions are routine option grants with vesting.

The Form 4 reports contemporaneous option acquisitions dated 08/18/2025: options exercisable for 10,452, 4,935, and 7,621 shares at $2.76, $2.76, and $6.81 respectively. The reporting person holds 23,008 shares directly after these transactions and notes indirect trust holdings of 104,525 shares. Vesting terms are typical: 1/48th monthly vesting schedules and one tranche subject to IPO contingency. For investors, this filing documents insider participation and standard equity compensation mechanics; it does not state sales or dilution metrics beyond the reported figures.

Corporate Governance Specialist

TL;DR: The disclosure shows executive equity alignment via option grants and trust holdings, with customary vesting and an IPO-contingent tranche.

The reporting identifies the individual as a director and SVP, Biological Sciences, filing as a single reporting person. The trust disclosure includes a disclaimer of beneficial ownership except for pecuniary interest, which is standard. The presence of an IPO-contingent vesting provision indicates some awards tied to corporate liquidity events. No departures, sales, or unusual transfer restrictions are disclosed. The filing is consistent with routine executive equity reporting requirements.

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^*

Klein Uwe

(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)
	SVP, Biological Sciences

3. Date of Earliest Transaction (Month/Day/Year)
08/18/2025

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	08/18/2025		M		10,452	A	$2.76	10,452	D
Common Stock	08/18/2025		M		4,935	A	$2.76	15,387	D
Common Stock	08/18/2025		M		7,621	A	$6.81	23,008	D
Common Stock								104,525	I	See footnote(1)

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)	$2.76	08/18/2025		M			10,452	(2)	11/11/2033	Common Stock	10,452	$0	10,453	D
Stock Option (Right to Buy)	$2.76	08/18/2025		M			4,935	(3)	03/19/2034	Common Stock	4,935	$0	9,001	D
Stock Option (Right to Buy)	$6.81	08/18/2025		M			7,621	(4)	09/22/2034	Common Stock	7,621	$0	33,027	D

Explanation of Responses:

1. 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.

2. 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.

3. 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.

4. 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.

	/s/ Ran Xiao, Attorney-in-Fact	08/19/2025
	** 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).
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 Uwe Klein acquire on 08/18/2025?

The filing reports option acquisitions exercisable for 10,452, 4,935, and 7,621 shares and corresponding acquisitions of common stock, leading to 23,008 shares directly owned following the transactions.

At what exercise prices were the Septerna options granted to Uwe Klein?

The reported exercise prices are $2.76 for two option tranches and $6.81 for the third tranche.

Does Uwe Klein have additional Septerna shares through a trust?

Yes. The Form 4 discloses 104,525 shares held by the Klein 2024 Revocable Trust, of which he is a co-trustee; he disclaims beneficial ownership except to the extent of pecuniary interest.

Are there vesting conditions for the reported option awards?

Yes. Footnotes describe 1/48th monthly vesting schedules for the tranches, and one tranche vests contingent upon the company completing an IPO.

Who signed the Form 4 for the reporting person?

The Form 4 was signed by Ran Xiao, Attorney-in-Fact, on behalf of the reporting person on 08/19/2025.