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

Rhea-AI Filing Summary

89bio (ETNB) director Lota S. Zoth reported derivative transactions tied to the closing of Roche’s acquisition on October 30, 2025. The deal paid $14.50 per share in cash, plus one non‑tradeable contingent value right (CVR) for potential payments of up to $6.00 per share upon specified milestones.

Per the merger terms, each outstanding stock option became fully vested and, if unexercised at closing, was cancelled and converted into the right to receive cash equal to the excess of the $14.50 cash amount over its exercise price, plus one CVR for each underlying share. Options with exercise prices ≥ $14.50 and < $20.50 were entitled to CVRs and potential milestone cash if thresholds are met. Options with exercise prices ≥ $20.50 were cancelled without payment or CVR.

Table II shows dispositions of multiple stock option grants (e.g., 20,000 at $24.05, 12,500 at $24.16, 25,000 at $2.64, 27,400 at $14.70, 45,150 at $9.98, 56,400 at $9.60), with post‑transaction derivative holdings reported as 0.

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

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X

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^*

Zoth Lota S.

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
10/30/2025

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

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)	$24.05	10/30/2025		D			20,000	(1)(2)(3)(4)(5)	06/12/2030	Common Stock	20,000	$0	0	D
Stock Option (Right to Buy)	$24.16	10/30/2025		D			12,500	(1)(2)(3)(4)(5)	04/15/2031	Common Stock	12,500	$0	0	D
Stock Option (Right to Buy)	$2.64	10/30/2025		D			25,000	(1)(2)(3)(4)(5)	05/16/2032	Common Stock	25,000	$0	0	D
Stock Option (Right to Buy)	$14.7	10/30/2025		D			27,400	(1)(2)(3)(4)(5)	02/09/2033	Common Stock	27,400	$0	0	D
Stock Option (Right to Buy)	$9.98	10/30/2025		D			45,150	(1)(2)(3)(4)(5)	02/01/2034	Common Stock	45,150	$0	0	D
Stock Option (Right to Buy)	$9.6	10/30/2025		D			56,400	(1)(2)(3)(4)(5)	02/01/2035	Common Stock	56,400	$0	0	D

Explanation of Responses:

1. Disposed of pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 17, 2025, by and among 89bio, Inc. (the "Issuer"), Roche Holdings, Inc. ("Parent") and Bluefin Merger Subsidiary, Inc., a wholly owned subsidiary of Parent ("Merger Sub"). On October 30, 2025, Parent and Merger Sub completed a tender offer pursuant to the terms of the Merger Agreement for all outstanding shares of common stock of the Issuer (each, a "Share") for an offer price of (i) $14.50 per Share in cash, without interest (the "Closing Amount") less any required withholding taxes, plus (ii) one non-tradeable contingent value right (each, a "CVR") representing the right to receive certain contingent payments of up to an aggregate amount of $6.00 per Share, [continues to Footnote 2]

2. [continues from Footnote 1] in cash, without interest less any required withholding taxes, upon the achievement of specified milestones on or prior to the applicable milestone outside dates, subject to and in accordance with the terms of the Contingent Value Rights Agreement (the "CVR Agreement"). Merger Sub thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent (the "Merger").

3. As of immediately prior to and conditioned upon the occurrence of the effective time of the Merger, pursuant to the Merger Agreement, each outstanding option to purchase Shares (each, an "Option") became fully vested and exercisable, and to the extent not exercised prior to the effective time of the Merger, was cancelled and converted into the right to receive (i) an amount in cash (without interest and subject to deduction for any required withholding taxes) equal to the product of (A) an amount equal to the excess of the Closing Amount over the exercise price per Share with respect to such Option and (B) the number of Shares subject to such Option plus (ii) one CVR with respect to each Share subject to such Option (the "Option Consideration"); provided, however, that if the exercise price per Share of any Option was equal to or greater than the Closing Amount, but less than $20.50 (any such option, an "Out of the Money Option"), [continues to Footnote 4]

4. [Continues from Footnote 3] such Out of the Money Option was not entitled to any payment of the Closing Amount in respect thereof and each Out of the Money Option was converted into the right to receive the CVR included in the Option Consideration with respect to each Share underlying such Out of the Money Option and became entitled to receive, at each time a milestone payment becomes due and payable under the terms of the CVR Agreement, an amount in cash equal to the product of (i) the number of Shares subject to such Out of the Money Option, and (ii) the amount, if any, by which (A) the Closing Amount plus the applicable milestone payment plus any other milestone payment that previously became due and payable under the terms of the CVR Agreement exceeds (B) the exercise price per Share with respect to such Out of the Money Option plus the amounts, [continues to Footnote 5]

5. [Continues from Footnote 4] if any, paid to such Option holder with respect to such CVR in respect of any milestone payments that previously became due and payable under the terms of the CVR Agreement; provided further, that any Option with an exercise price that was equal to or greater than $20.50, was cancelled immediately prior to the effective time of the Merger without the receipt of any payment of the Closing Amount or CVR in respect thereof.

	/s/ Ryan A. Murr, as attorney-in-fact for Lota S. Zoth	10/30/2025
	** Signature of Reporting Person	Date
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FAQ

What did 89bio (ETNB) disclose in this Form 4?

A director reported option dispositions tied to Roche’s acquisition, reflecting cancellation/convert-and-pay mechanics under the merger agreement.

What were the cash and CVR terms for 89bio shareholders?

The consideration was $14.50 per share in cash plus one CVR for potential milestone payments up to $6.00 per share.

How were stock options treated at closing?

Unexercised options vested and were cancelled for cash equal to $14.50 minus the exercise price per share, plus one CVR per underlying share, subject to terms.

What happened to options with higher exercise prices?

Options with exercise prices ≥ $14.50 and < $20.50 received CVRs; options with exercise prices ≥ $20.50 were cancelled without payment or CVR.

What specific option grants were reported as disposed?

Grants included 20,000 at $24.05; 12,500 at $24.16; 25,000 at $2.64; 27,400 at $14.70; 45,150 at $9.98; 56,400 at $9.60.

What is the director’s derivative position after the transactions?

Derivative securities beneficially owned following the reported transactions were 0.