Jade Biosciences, Inc.
19.99%
14,069,494
1798749
Jun 4, 2026
Jun 9, 2026, 05:30 PM
Reporting Persons (5)
This is a joint filing. The reported shares may overlap between reporting persons and should not be summed.
| Name | Type | % of Class | Aggregate | Sole Voting | Shared Voting |
|---|---|---|---|---|---|
| Fairmount Funds Management LLC | Investment Adviser | 19.99% | 14,069,494 | 0 | 14,069,494 |
| Peter Evan Harwin | Individual | 19.99% | 14,069,494 | 0 | 14,069,494 |
| Tomas Kiselak | Individual | 19.99% | 14,063,511 | 23,017 | 14,040,494 |
| Fairmount Healthcare Fund II L.P. | Partnership | 16.22% | 11,413,677 | 0 | 11,413,677 |
| Fairmount Healthcare Co-Invest IV L.P. | Partnership | 4.36% | 2,655,817 | 0 | 2,655,817 |
Disclosure Items (4)
Common Stock, $0.0001 par value per share
Jade Biosciences, Inc.
221 Crescent Street, Waltham, MA, 02453
The information in rows 11 and 13 of each of the cover pages (including the explanatory note in the "Comments") of this Amendment No. 2 is incorporated by reference herein. The Reporting Persons' securities (a) include (i) 1,897,677 shares of Common Stock and 9,487,000 shares of Common Stock issuable upon conversion of 9,487 shares of Series A Preferred Stock, directly held by Fund II, and (ii) 2,655,817 shares of Common Stock directly held by Co-Invest, and (b) exclude (i) 5,790,206 shares of Common Stock issuable upon exercise of Pre-Funded Warrants and (ii) 3,135,000 shares of Common Stock issuable upon conversion of 3,135 shares of Series A Preferred Stock, in each case directly held by Fund II. The exercise of the Pre-Funded Warrants is subject to a beneficial ownership limitation of 9.99% of the outstanding Common Stock and the conversion of the Series A Preferred Stock is subject to a beneficial ownership limitation of 19.99%. The securities exclude shares of Common Stock issuable upon exercise of Pre-Funded Warrants and conversion of shares of Series A Preferred Stock in excess of such beneficial ownership limitations. At such time as Fairmount and its affiliates beneficially own 9.0% or less of the Common Stock, the beneficial ownership limitation with respect to the Series A Preferred Stock will automatically reduce to 9.99%.
The information in rows 7 through 10 of each of the cover pages of this Amendment No. 2 is incorporated by reference herein.
On April 29, 2026, Mr. Kiselak's stock options to purchase 23,017 shares of Common Stock at an exercise price of $10.14 per share, received as compensation for his service as a director of the Company, vested in full and became exercisable.
Lock-Up Agreement In connection with the Company's underwritten public offering of common stock that closed on June 5, 2026, the Reporting Persons entered into a customary lock-up letter agreement (the "Lock-Up Agreement") with Jefferies LLC, TD Securities (USA) LLC, and UBS Securities LLC, acting as the representatives of the underwriters (collectively, the "Representatives") to an underwriting agreement with the Company. Pursuant to the Lock-Up Agreement, the Reporting Persons agreed to refrain from selling shares of the Company's securities without the consent of the Representatives, and other customary lock-up conditions, for a period of 60 days following the date of the final prospectus supplement for the offering. The Reporting Persons did not purchase any securities of the Company or otherwise participate in the offering. The foregoing description of the Lock-Up Agreement does not purport to be complete and is qualified in its entirety by reference to the Form of Lock-Up Agreement, which is filed as Exhibit 99.2 to this Schedule 13D and incorporated herein by reference.
99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 of the Reporting Persons' Schedule 13D filed with the SEC on October 8, 2025). 99.2 Lock-Up Agreement (incorporated by reference to Exhibit A to the Underwriting Agreement filed as Exhibit 1.1 of the Company's Form 8-K filed with the SEC on June 4, 2026).