89bio, Inc. — Director's Dealing 2025

Oct 30, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: 89bio, Inc. (ETNB)
CIK: 0001785173
Period of Report: 2025-10-30

Reporting Person: Hayden Michael R (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-10-30	Common Stock	U	80904	—	Disposed	0	Direct
2025-10-30	Common Stock	U	103978	—	Disposed	0	Indirect
2025-10-30	Common Stock	U	61538	—	Disposed	0	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-10-30	Stock Option (Right to Buy)	$1.93	D	27647	Disposed	2028-11-09	Common Stock (27647)	Direct
2025-10-30	Stock Option (Right to Buy)	$1.93	D	2933	Disposed	2029-01-30	Common Stock (2933)	Direct
2025-10-30	Stock Option (Right to Buy)	$3.11	D	22730	Disposed	2029-07-30	Common Stock (22730)	Direct
2025-10-30	Stock Option (Right to Buy)	$21.4	D	7000	Disposed	2030-04-05	Common Stock (7000)	Direct
2025-10-30	Stock Option (Right to Buy)	$24.29	D	7000	Disposed	2030-06-22	Common Stock (7000)	Direct
2025-10-30	Stock Option (Right to Buy)	$24.16	D	12500	Disposed	2031-04-15	Common Stock (12500)	Direct
2025-10-30	Stock Option (Right to Buy)	$2.64	D	25000	Disposed	2032-05-16	Common Stock (25000)	Direct
2025-10-30	Stock Option (Right to Buy)	$14.7	D	27400	Disposed	2033-02-09	Common Stock (27400)	Direct
2025-10-30	Stock Option (Right to Buy)	$9.98	D	45150	Disposed	2034-02-01	Common Stock (45150)	Direct
2025-10-30	Stock Option (Right to Buy)	$9.6	D	56400	Disposed	2035-02-01	Common Stock (56400)	Direct

Footnotes

F1: 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]

F2: [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") (the Closing Amount plus one CVR, collectively, the "Offer Price"). 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"). At the effective time of the Merger, each issued and outstanding Share (other than any Excluded Shares (as such term is defined in the Merger Agreement)) was cancelled in exchange for the right to receive the Offer Price.

F3: These shares are held directly by Genworks 2 Consulting Inc., over which the Reporting Person's wife has sole voting and investment power.

F4: These shares are held directly by The Hayden Family Trust, over which the Reporting Person's wife has sole voting and investment power.

F5: 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 6]

F6: [Continues from Footnote 5] 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 7]

F7: [Continues from Footnote 6] 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.