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  4. [Form 4] 89bio, Inc. Insider Trading Activity

ETNB CFO option exercises update direct holdings to 339,295 shares

Filing Impact
(High)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

89bio (ETNB) reported insider activity by CFO Ryan Martins on 10/22/2025. He exercised stock options for 76,901 shares at $3.11 and 3,898 shares at $4.44, increasing his directly held common stock to 339,295 shares after the transactions.

The $3.11 option position is now 0 following exercise, while 48,102 options remain from the $4.44 grant. The filing notes an administrative error previously omitted the exercise of an aggregate of 5,000 options from a March 27, 2023 report; this filing corrects the reported holdings.

Positive

  • None.

Negative

  • None.
Insider Martins Ryan
Role Chief Financial Officer
Type Security Shares Price Value
Exercise Stock Option (Right to Buy) 76,901 $0.00 --
Exercise Stock Option (Right to Buy) 3,898 $0.00 --
Exercise Common Stock 76,901 $3.11 $239K
Exercise Common Stock 3,898 $4.44 $17K
Holdings After Transaction: Stock Option (Right to Buy) — 0 shares (Direct); Common Stock — 335,397 shares (Direct)
Footnotes (1)
  1. Due to an administrative error, the exercise of an aggregate of 5,000 options was erroneously omitted from the Form 4 filed by the Reporting Person on March 27, 2023. This form reflects the correct amount of common stock owned by the Reporting Person. This option is vested in full. Due to an administrative error, the exercise of an aggregate of 5,000 options was erroneously omitted from the Form 4 filed by the Reporting Person on March 27, 2023. This form reflects the correct amount of stock options owned by the Reporting Person. This option represents a right to purchase a total of 52,000 shares of the Issuer's Common Stock, one quarter of which vested on February 17, 2023, with the remaining three quarters vesting in equal quarterly installments over the following three years, subject to the Reporting Person's continued service to the Issuer.
Form 4 Insider Transactions: What Each Field Means →
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*
Martins Ryan
(Last) (First) (Middle)
C/O 89BIO, INC.
655 MONTGOMERY STREET, SUITE 1500
(Street)
SAN FRANCISCO CA 94111
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
89bio, Inc. [ ETNB ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
Chief Financial Officer
3. Date of Earliest Transaction (Month/Day/Year)
10/22/2025
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 10/22/2025 M 76,901 A $3.11 335,397(1) D
Common Stock 10/22/2025 M 3,898 A $4.44 339,295 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) $3.11 10/22/2025 M 76,901 (2) 07/30/2029 Common Stock 76,901 $0.00 0(3) D
Stock Option (Right to Buy) $4.44 10/22/2025 M 3,898 (4) 02/16/2032 Common Stock 3,898 $0.00 48,102 D
Explanation of Responses:
1. Due to an administrative error, the exercise of an aggregate of 5,000 options was erroneously omitted from the Form 4 filed by the Reporting Person on March 27, 2023. This form reflects the correct amount of common stock owned by the Reporting Person.
2. This option is vested in full.
3. Due to an administrative error, the exercise of an aggregate of 5,000 options was erroneously omitted from the Form 4 filed by the Reporting Person on March 27, 2023. This form reflects the correct amount of stock options owned by the Reporting Person.
4. This option represents a right to purchase a total of 52,000 shares of the Issuer's Common Stock, one quarter of which vested on February 17, 2023, with the remaining three quarters vesting in equal quarterly installments over the following three years, subject to the Reporting Person's continued service to the Issuer.
/s/ Ryan A. Murr, as attorney-in-fact for Ryan Martins 10/23/2025
** 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.

Source: View Original Filing on SEC EDGAR

FAQ

What did 89bio (ETNB) disclose about the CFO's transactions?

CFO Ryan Martins exercised options for 76,901 shares at $3.11 and 3,898 shares at $4.44 on 10/22/2025.

How many 89bio (ETNB) shares does the CFO hold after the transactions?

He beneficially owns 339,295 shares directly after the reported transactions.

What remains of the CFO's 89bio (ETNB) options after the exercise?

The $3.11 option is now 0; 48,102 options remain from the $4.44 grant.

Were there any corrections noted in the 89bio (ETNB) filing?

Yes. It states an administrative error omitted the exercise of an aggregate of 5,000 options from a March 27, 2023 report.

What is the role of the reporting person at 89bio (ETNB)?

He is an Officer, serving as Chief Financial Officer.

What are the expiration dates for the options listed?

The exercised $3.11 option had an expiration of 07/30/2029; the $4.44 grant has an expiration of 02/16/2032.