Jade Biosciences, Inc.

Item 5. Other Information.

Open Market Sale Agreement

On May 7, 2026, we entered into an Open Market Sale Agreement SM (the “Sales Agreement”), with Jefferies LLC (the “Sales Agent”), under which we may, from time to time, sell shares of our common stock having an aggregate offering price of up to $200.0 million in “at the market” offerings through the Sales Agent. Sales of the shares of common stock, if any, will be made at prevailing market prices at the time of sale or as otherwise agreed with the Sales Agent. The Sales Agent will receive a commission from us of up to 3.0% of the gross proceeds of any shares of common stock sold under the Sales Agreement. Sales of our common stock made pursuant to the Sales Agreement will be made under our shelf registration statement on Form S-3 (the “Registration Statement”) which is expected be filed with the U.S. Securities and Exchange Commission (the “SEC”) on May 7, 2026 at such time as it is declared effective by the SEC. We are not obligated to sell, and the Sales Agent is not obligated to buy or sell, any shares of our common stock under the Sales Agreement, and we may at any time suspend offers under the Sales Agreement or terminate the Sales Agreement.

The foregoing description of the Sales Agreement is not complete and is qualified in its entirety by reference to the Sales Agreement, a copy of which will be filed as Exhibit 1.2 to the Registration Statement and is incorporated herein by reference.