Form 4: Fairmount Funds Boosts Stake in Jade Biosciences

Fairmount Funds Management and affiliated entities acquired over 1.3 million common shares and 855,000 pre-funded warrants in Jade Biosciences via a private placement.

Summary

• Fairmount Funds Management LLC, Fairmount Healthcare Fund II L.P., Fairmount Healthcare Co-Invest IV L.P., Tomas Kiselak, and Peter Evan Harwin reported changes in beneficial ownership of Jade Biosciences, Inc. (JBIO).
• The transaction involved the acquisition of 1,333,126 shares of Common Stock at a price of $9.14 per share.
• Additionally, 855,047 Pre-Funded Warrants were acquired, exercisable at $0.0001 per share, with an underlying value of $9.1399 per warrant.
• The acquisitions occurred on October 6, 2025, through a private placement from the Issuer.
• Following the transaction, Fairmount Healthcare Fund II L.P. beneficially owns 1,897,677 shares of Common Stock and 855,047 Pre-Funded Warrants indirectly.
• Fairmount Healthcare Co-Invest IV L.P. beneficially owns 2,655,817 shares of Common Stock indirectly.
• The Pre-Funded Warrants have no expiration date and are exercisable at any time, subject to a 9.99% beneficial ownership limitation.
• Tomas Kiselak, a Managing Member of Fairmount Funds Management LLC, serves on the board of directors of Jade Biosciences, Inc., establishing Fairmount as a director by deputization.

Sentiment

Score: 9

Explanation: The significant investment by a 10% owner and director, Fairmount Funds Management LLC, through a private placement, indicates strong insider confidence and a positive outlook for Jade Biosciences. This is generally viewed very favorably by the market.

Positives

• Significant investment by a 10% owner and director (Fairmount Funds Management LLC and its affiliates) signals strong confidence in Jade Biosciences' future.
• The acquisition of 1,333,126 common shares and 855,047 pre-funded warrants at a specific price point ($9.14 per share for common stock) provides a clear valuation benchmark for the transaction.
• The private placement structure indicates direct capital infusion into the company, which can strengthen its balance sheet.

Negatives

• The private placement could lead to some dilution for existing shareholders, although the extent is not detailed in this filing.

Risks

• The Pre-Funded Warrants include a beneficial ownership limitation, preventing exercise if the holder would own more than 9.99% of outstanding common stock, which could restrict immediate full conversion.

Future Outlook

The Pre-Funded Warrants acquired have no expiration date and are exercisable at any time after issuance, providing flexibility for future conversion into common stock, subject to beneficial ownership limitations.

Management Comments

• Fairmount Funds Management LLC is the investment manager for Fairmount Healthcare Fund II L.P. and Fairmount Healthcare Co-Invest IV L.P., with Peter Harwin and Tomas Kiselak as its managers.
• Fairmount, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any reported securities, except to the extent of their pecuniary interest therein.
• Fairmount may be deemed a director by deputization of Jade Biosciences by virtue of Tomas Kiselak serving on the board of directors of the Issuer and also being a Managing Member of Fairmount.

Industry Context

This insider transaction, involving a significant investment by a major shareholder and director, typically signals strong internal confidence in the company's prospects, often viewed positively by the market. Private placements are common methods for companies to raise capital directly from institutional investors.

Comparison to Industry Standards

• Not applicable for this type of filing as it reports an insider transaction rather than operational or financial performance.

Related Party Transactions

• The acquisition of securities by Fairmount Funds Management LLC and its affiliates constitutes a related-party transaction, as Fairmount is a 10% owner and has a director (Tomas Kiselak) serving on the board of Jade Biosciences, Inc.

Stakeholder Impact

• Shareholders may view this as a positive signal, indicating strong institutional backing and confidence from a significant investor and board member.
• The company benefits from the capital raised through the private placement.

Next Steps

• Holders of Pre-Funded Warrants may exercise them at any time, subject to the 9.99% beneficial ownership limitation.

Key Dates

Recommendation

The substantial investment by a 10% owner and director, Fairmount Funds Management LLC, through a private placement, is a powerful signal of conviction in Jade Biosciences' future prospects. Insider buying of this magnitude, especially by a sophisticated institutional investor with board representation, often precedes positive company developments and is a strong indicator for potential stock appreciation. This transaction suggests that those closest to the company believe its shares are undervalued or poised for growth.

Keywords

Jade Biosciences, JBIO, Fairmount Funds Management, Insider Buying, Form 4, Private Placement, Common Stock, Pre-Funded Warrants, Beneficial Ownership, Director by Deputization