Sell4

Septerna, Inc.

SEPN

Total Value

$133.3K

Net $114.9K sold

Filing Date

Aug 5, 2026

2 transactions

Sales

$114.9K

2 transactions

Trade Summary

On Aug 3, 2026, Long Daniel D., Insider, sold $133.3K of Septerna, Inc. (SEPN) across 2 transactions. The filing covers Common Stock and reflects net selling of $114.9K. Reported prices ranged from $2.76 to $34.68. Insider transactions are sourced from SEC Form 4 disclosures and should be reviewed alongside company fundamentals and the insider's broader trading history.

Price at the Time of the Trade

SEPN daily price with the insider's sale marked at $34.47.

Sold in the upper half of the 6-month range · the stock trades 12% higher today.

Price data is delayed and provided for context only — not investment advice.

Insider Information

Name: Long Daniel D.
Role: Insider
Location: SOUTH SAN FRANCISCO, CA

Filing Details

Filing Date: Aug 5, 2026
Transaction Date: Aug 3, 2026
Accession Number: 0001193125-26-335820
Form Type: 4
Net Trading Amount: -$114.9K

Non-Derivative Transactions

Date	Security	Shares	Price	Type	Value
Aug 3, 2026	Common Stock	1,816	$2.76	Exercise	$5.0K
Aug 3, 2026	Common Stock	1,518	$2.76	Exercise	$4.2K
Aug 3, 2026	Common Stock	1,000	$33.98	Sale	$34.0K
Aug 3, 2026	Common Stock	2,334	$34.68	Sale	$80.9K

Derivative Transactions

Date	Security	Shares	Exercise Price	Type	Value
Aug 3, 2026	SEPN derivative	1,816	$2.76	Exercise	$5.0K
Aug 3, 2026	SEPN derivative	1,518	$2.76	Exercise	$4.2K

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Footnotes

(F1)This transaction was effected pursuant to a Rule 10b5-1 sales plan adopted by the Reporting Person on March 20, 2026.
(F2)The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $33.39 to $34.32. 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 sold at each separate price within the range.
(F3)The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $34.43 to $35.04. 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 sold at each separate price within the range.
(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 August 1, 2023, subject to the Reporting Person's continuous service to the Issuer on each such date.
(F5)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.

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^*

Long Daniel D.

(Last)

(First)

(Middle)

C/O SEPTERNA, INC.

250 EAST GRAND AVENUE

(Street)

SOUTH SAN FRANCISCO

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, Drug Discovery

3. Date of Earliest Transaction (Month/Day/Year)
08/03/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/03/2026		M		1,816	A	$2.76	98,228	D
Common Stock	08/03/2026		M		1,518	A	$2.76	99,746	D
Common Stock	08/03/2026		S⁽¹⁾		1,000	D	$33.9756⁽²⁾	98,746	D
Common Stock	08/03/2026		S⁽¹⁾		2,334	D	$34.6805⁽³⁾	96,412	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock Option (Right to Buy)	$2.76	08/03/2026		M			1,816	⁽⁴⁾	11/11/2033	Common Stock	1,816	$0	5,227	D
Stock Option (Right to Buy)	$2.76	08/03/2026		M			1,518	⁽⁵⁾	03/19/2034	Common Stock	1,518	$0	12,418	D

Explanation of Responses:

1. This transaction was effected pursuant to a Rule 10b5-1 sales plan adopted by the Reporting Person on March 20, 2026.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $33.39 to $34.32. 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 sold at each separate price within the range.

3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $34.43 to $35.04. 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 sold at each separate price within the range.

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 August 1, 2023, subject to the Reporting Person's continuous service to the Issuer on each such date.

5. 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.

	/s/ Mark A. Wilson, Attorney-in-Fact	08/05/2026
	** 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.

Form 4 as rendered by the SEC from accession 0001193125-26-335820.

Septerna, Inc.

Trade Summary

Price at the Time of the Trade

Company Information

Insider Information

Filing Details

Non-Derivative Transactions

Derivative Transactions

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Footnotes

SEC Form 4

SEC Filing

Price at the Time of the Trade

SEC Form 4