Jade Biosciences, Inc.

As filed with the Securities and Exchange Commission on December 22, 2025

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

221 Crescent St., Building 23

Suite 105

Waltham,

MA

(781)

312-3013

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Tom Frohlich

221 Crescent St., Building 23

Suite 105

Waltham,

MA

(781)

312-3013

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Cheston Larson

Matt Bush

Anthony Gostanian

Latham & Watkins LLP

12670 High Bluff Drive

San Diego, CA 92130

(858) 523-5400

Approximate date of commencement of proposed sale to the public

: From time to time after the effective date of this Registration Statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a

non-accelerated

filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule

12b-2

of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.☒

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment that specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until this registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. The selling stockholder named in this prospectus may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED December 22, 2025

PRELIMINARY PROSPECTUS

3,214,286 Shares

Offered by the Selling Stockholder

This prospectus relates to the proposed resale or other disposition by the selling stockholder identified herein (the “Selling Stockholder”) of up to 3,214,286 shares (the “Resale Shares”) of our common stock, par value $0.0001 per share (“Common Stock”).

The Resale Shares were issued and sold to an accredited investor in a private placement (the “December 2025 PIPE”), which closed on December 16, 2025. We are not selling any Resale Shares under this prospectus and will not receive any of the proceeds from the sale or other disposition of Resale Shares by the Selling Stockholder.

The Selling Stockholder may sell the Resale Shares on any national securities exchange or quotation service on which the securities may be listed or quoted at the time of sale, on theover-the-counter market, in one or more transactions otherwise than on these exchanges or systems, such as privately negotiated transactions, or using a combination of these methods, and at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale, or at negotiated prices. See the disclosure under the heading “Plan of Distribution” elsewhere in this prospectus for more information about how the Selling Stockholder may sell or otherwise dispose of its Resale Shares hereunder.

The Selling Stockholder may sell any, all or none of the securities offered by this prospectus and we do not know when or in what amount the Selling Stockholder may sell its Resale Shares hereunder following the effective date of the registration statement of which this prospectus forms a part. Discounts, concessions, commissions and similar selling expenses attributable to the sale of the Resale Shares will be borne by the Selling Stockholder. We will pay certain fees and expenses (other than discounts, concessions, commissions and similar selling expenses) incident to the registration of the Resale Shares with the Securities and Exchange Commission (“SEC”).

You should carefully read this prospectus and any applicable prospectus supplement before you invest in any of the securities being offered.

Our Common Stock is traded on The Nasdaq Capital Market under the symbol “JBIO.” On December 19, 2025, the last reported sale price for our Common Stock was $17.03 per share.

An investment in our securities involves a high degree of risk. You should carefully consider the information under the heading “Risk Factors” beginning on page 8 of this prospectus and any applicable prospectus supplement.

We are a “smaller reporting company” and an “emerging growth company” under applicable federal securities laws and are subject to reduced public company reporting requirements.

Neither the SEC nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is , 2025