ZBIO (Nasdaq: ZBIO) updates Crown Helix resale registration

Rhea-AI Filing Summary

The company is permitting resale of up to 8,533 shares of its Common Stock held by Crown Helix Strategies Ltd. under this prospectus supplement. These shares were transferred to Crown Helix Strategies Ltd. in December 2025 as part of an internal reorganization involving Crown/Long Short 41 Segregated Portfolio.

The supplement removes Crown/Long Short 41 Segregated Portfolio as a selling stockholder and adds Crown Helix Strategies Ltd. instead, without changing any other selling stockholders. Shares of Common Stock outstanding were 53,679,166 as of October 31, 2025; this is a baseline figure, not the amount being offered.

Filed Pursuant to Rule 424(b)(7)
Registration No. 333-290999

PROSPECTUS SUPPLEMENT NO. 1

(To Prospectus dated October 21, 2025)

Common Stock

This Prospectus Supplement No. 1 (this “prospectus supplement”) amends and supplements information contained or incorporated by reference in the prospectus, dated October 21, 2025 (the “prospectus”). The selling stockholders may, from time to time, sell, transfer or otherwise dispose of any or all of their shares of our common stock, par value $0.0001 per share (the “Common Stock”) on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices. See “Plan of Distribution” which begins on page 19 of the prospectus.

This prospectus supplement should be read in conjunction with, and is qualified by reference to, the prospectus, except to the extent that information contained herein supersedes the information contained or incorporated by reference in the prospectus. This prospectus supplement may only be delivered or used in connection with, the prospectus.

The Common Stock is listed on the Nasdaq Global Select Market under the symbol “ZBIO.”

Investing in our securities involves risks. See “Risk Factors” beginning on page 4 of the prospectus and under similar headings in the other documents that are incorporated by reference into this prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is January 28, 2026

SELLING STOCKHOLDERS

The following information amends and supplements the information that appears under the heading “Selling Stockholders” beginning on page 10 of the prospectus. Capitalized terms used herein but not defined have the meanings ascribed to such terms in the prospectus.

This prospectus supplement provides that up to the number of shares of Common Stock set forth below may be resold by the selling stockholder named below.

In December 2025, Crown/Long Short 41 Segregated Portfolio, a selling stockholder included in the prospectus, transferred 8,533 shares of Common Stock purchased in the Private Placement to Crown Helix Strategies Ltd. in connection with an internal reorganization. The table that appears under the heading “Selling Stockholders” in the prospectus is being amended and supplemented to (i) remove Crown Managed Accounts SPC Acting for and on behalf of Crown/Long Short 41 Segregated Portfolio as a selling stockholder, and (ii) add the Crown Helix Strategies Ltd. as a selling stockholder. This prospectus supplement does not impact any other selling stockholders set forth in the table appearing under the heading “Selling Stockholders” in the prospectus.

The percentage ownership data is based on 53,679,166 shares of Common Stock outstanding as of October 31, 2025.

We have prepared the table below based on information given to us by, or on behalf of, the Crown Helix Strategies Ltd. on or before the date of this prospectus supplement.

Shares of Common Stock Beneficially Owned Prior to

Shares of Common

Beneficial Ownership After this Offering(3)

Name(1)

this Offering

​ Stock Offered(2)

Shares

%(4)

Crown Helix Strategies Ltd. (5)

21,921

8,533

13,388

*

* Less than one percent of outstanding Common Stock.

(1) All information regarding selling stockholders was provided by the selling stockholders

(2) The number of shares of Common Stock in the column “Shares of Common Stock Offered” represents all of the shares of Common Stock that a selling stockholder may offer and sell from time to time under this prospectus supplement.

(3) Assumes that all shares of Common Stock being registered under the registration statement of which this prospectus supplement forms a part are sold in this offering, and that none of the selling stockholders acquired additional shares of our Common Stock after the date of this prospectus supplement.

(4) Percentage ownership is based on 53,679,166 shares of Common Stock outstanding as of October 31, 2025.

(5) The shares reported under “Shares of Common Stock Beneficially Owned Prior to this Offering” consist of (i) 8,533 shares of Common Stock purchased by Crown Managed Accounts SPC acting for and on behalf of Crown/Long Short 41 Segregated Portfolio (“Crown”) and (ii) 13,388 shares of Common Stock held by Crown. Kamran Moghtaderi is the managing principal of the trading advisor to Crown/Long Short 41 Segregated Portfolio. The address of Crown is Grand Pavilion Commercial Centre, 802 West Bay Road, P.O Box 31490, KY1-1206, George Town, Grand Cayman, Cayman Islands.

FAQ

What does this ZBIO prospectus supplement change for selling stockholders?

It replaces one selling stockholder with another related entity while keeping overall resale terms intact. Crown/Long Short 41 Segregated Portfolio is removed as a selling stockholder, and Crown Helix Strategies Ltd. is added, reflecting an internal reorganization of ownership of certain Common Stock shares.

How many ZBIO shares may Crown Helix Strategies Ltd. resell under this supplement?

Crown Helix Strategies Ltd. may resell up to 8,533 shares of Common Stock under this supplement. That amount represents all shares shown in the “Shares of Common Stock Offered” column for Crown Helix and can be sold from time to time using the prospectus.

How many ZBIO shares did Crown Helix Strategies Ltd. hold before this offering?

Before this offering, Crown Helix Strategies Ltd. beneficially owned 21,921 shares of Common Stock. This total includes 8,533 shares purchased in the Private Placement and 13,388 additional shares held by Crown, as reported in the beneficial ownership table in the supplement.

What happened to Crown/Long Short 41 Segregated Portfolio’s ZBIO shares?

Crown/Long Short 41 Segregated Portfolio transferred 8,533 shares of Common Stock to Crown Helix Strategies Ltd. in December 2025. This was done in connection with an internal reorganization, and the supplement removes Crown/Long Short 41 Segregated Portfolio as a selling stockholder in the registration.

How many ZBIO Common Stock shares were outstanding as of October 31, 2025?

There were 53,679,166 shares of Common Stock outstanding as of October 31, 2025. This outstanding share count is used to calculate percentage ownership figures for the selling stockholders shown in the table in the prospectus supplement.

Where is ZBIO’s Common Stock listed and what is its trading symbol?

The company’s Common Stock is listed on the Nasdaq Global Select Market under the trading symbol “ZBIO”. Selling stockholders may sell their registered shares on this market, other trading facilities, or through private transactions as described in the plan of distribution.