Key facts
- This page summarizes Fairmount Funds Management LLC's Form 3 filing for Korsana Biosciences, Inc. (CYCN).
- 0 reported transactions and 10 derivative rows are listed below.
- Accepted by SEC: 10 Sep 2026, 17:30.
Fairmount Funds Management LLC - 08 Sep 2026 Form 3 Insider Report for Korsana Biosciences, Inc. (CYCN)
- Reporting relationship
- Director, 10%+ Owner
- Issuer ticker
- CYCN
- Reported as of
- 08 Sep 2026
- Net transaction value
- $0
- SEC form
- 3
- Accepted by SEC
- 10 Sep 2026, 17:30:11 UTC
- Prior SEC filing
- 03 Sep 2026
- Next SEC filing
- 10 Sep 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Peter Harwin, Managing Member of Fairmount Funds Management LLC
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
Fairmount Funds Management LLC filed Form 3 for Korsana Biosciences, Inc. (CYCN) on 10 Sep 2026.
Change
- Previous filing in this sequence was filed on 03 Sep 2026.
- Current net transaction value: $0.
Research use
- This tells you what this filing adds before you inspect full transaction and derivative tables.
- You can trace every row back to the original SEC filing document.
Evidence
Official SEC source
View source filing
Ownership activity is grounded in SEC Form 3 disclosures.
Reporting Owners (5)
CIK 0001802528
Primary reporting owner
Fairmount Funds Management LLC
- Relationship
- Director, 10%+ Owner
- Address
- 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
- Signature
- /s/ Peter Harwin, Managing Member of Fairmount Funds Management LLC
- Signature date
- 10 Sep 2026
CIK 0001769651
Fairmount Healthcare Fund II L.P.
- Relationship
- Director, 10%+ Owner
- Address
- 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
- Signature
- /s/ Peter Harwin, Managing Member of Fairmount Healthcare Fund II L.P.
- Signature date
- 10 Sep 2026
CIK 0002124208
Fairmount Healthcare Co-Invest VI L.P.
- Relationship
- Director, 10%+ Owner
- Address
- 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
- Signature
- /s/ Peter Harwin, Managing Member of Fairmount Healthcare Co-Invest VI L.P.
- Signature date
- 10 Sep 2026
CIK 0001830177
Kiselak Tomas
- Relationship
- Director, 10%+ Owner
- Address
- 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
- Signature
- /s/ Tomas Kiselak
- Signature date
- 10 Sep 2026
CIK 0001663607
Harwin Peter Evan
- Relationship
- Director, 10%+ Owner
- Address
- 200 BARR HARBOR DRIVE, SUITE 400, WEST CONSHOHOCKEN
- Signature
- /s/ Peter Harwin
- Signature date
- 10 Sep 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 6,911,174
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 6,911,174
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 6,911,174
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 6,911,174
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 6,911,174
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,192,555
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Co-Invest VI L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,192,555
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Co-Invest VI L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,192,555
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Co-Invest VI L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,192,555
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Co-Invest VI L.P.
- Footnotes
- F1, F2, F3
CYCN
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,192,555
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Co-Invest VI L.P.
- Footnotes
- F1, F2, F3
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
CYCN
holding
Derivative
Series B Non-Voting Preferred Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 2,074,000
- Exercise price
- Footnotes
- F1, F3, F4, F5, F6
CYCN
holding
Derivative
Series B Non-Voting Preferred Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 2,074,000
- Exercise price
- Footnotes
- F1, F3, F4, F5, F6
CYCN
holding
Derivative
Series B Non-Voting Preferred Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 2,074,000
- Exercise price
- Footnotes
- F1, F3, F4, F5, F6
CYCN
holding
Derivative
Series B Non-Voting Preferred Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 2,074,000
- Exercise price
- Footnotes
- F1, F3, F4, F5, F6
CYCN
holding
Derivative
Series B Non-Voting Preferred Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 2,074,000
- Exercise price
- Footnotes
- F1, F3, F4, F5, F6
CYCN
holding
Derivative
Pre-funded Warrant
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 66,436
- Exercise price
- $0.000100
- Footnotes
- F1, F3, F7, F8, F9
CYCN
holding
Derivative
Pre-funded Warrant
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 66,436
- Exercise price
- $0.000100
- Footnotes
- F1, F3, F7, F8, F9
CYCN
holding
Derivative
Pre-funded Warrant
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 66,436
- Exercise price
- $0.000100
- Footnotes
- F1, F3, F7, F8, F9
CYCN
holding
Derivative
Pre-funded Warrant
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 66,436
- Exercise price
- $0.000100
- Footnotes
- F1, F3, F7, F8, F9
CYCN
holding
Derivative
Pre-funded Warrant
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 08 Sep 2026
- Ownership
- By Fairmount Healthcare Fund II L.P.
- Underlying class
- Common Stock
- Underlying amount
- 66,436
- Exercise price
- $0.000100
- Footnotes
- F1, F3, F7, F8, F9
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Explanation of responses 9 footnotes
Footnote F1
Effective as of September 8, 2026 (the "Effective Time"), (i) Cariboos Merger Sub Corp., a wholly owned subsidiary of Cyclerion Therapeutics, Inc. ("Cyclerion"), merged with and into Korsana Biosciences, Inc. ("Pre-Merger Korsana"), with Pre-Merger Korsana continuing as a wholly owned subsidiary of Cyclerion and the surviving corporation of the merger (the "First Merger"), and (ii) immediately thereafter, Pre-Merger Korsana merged with and into Cariboos Merger Sub II, LLC, a second wholly owned subsidiary of Cyclerion ("Second Merger Sub"), with Second Merger Sub being the surviving entity of the merger under the name Korsana Biosciences Operating Company, LLC (the "Second Merger" and, together with the First Merger, the "Merger"). At the Effective Time, Cyclerion changed its name to "Korsana Biosciences, Inc." (hereinafter, the "Issuer").
Footnote F2
Represents the number of shares of the Issuer's common stock received by the Reporting Person in the Merger in exchange for the shares of Pre-Merger Korsana's common stock held by the Reporting Person prior to the Merger. Each share of Pre-Merger Korsana's common stock held at the Effective Time was exchanged for 0.2074 shares of the Issuer's common stock.
Footnote F3
Fairmount Funds Management LLC ("Fairmount") is the investment manager for Fairmount Healthcare Fund II L.P. and Fairmount Healthcare Co-Invest VI L.P. Peter Harwin and Tomas Kiselak are the managers of Fairmount. Fairmount, Mr. Harwin and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.
Footnote F4
Series B Non-Voting Convertible Preferred Stock of the Issuer, no par value per share (the "Issuer Preferred Stock"), has no expiration date and is convertible at any time and from time to time at the option of the holder thereof into a number of shares of the Issuer's common stock equal to the Conversion Ratio, initially 1,000 shares of common stock for each share of Issuer Preferred Stock, subject to adjustment. A holder may not convert Issuer Preferred Stock to the extent that, after giving effect to the conversion, the holder, together with its affiliates and any other persons whose beneficial ownership would be aggregated with the holder's for purposes of Section 13(d) or Section 16 of the Securities Exchange Act of 1934, including any group of which the holder is a member, would beneficially own shares of common stock in excess of the applicable beneficial ownership limitation, which the Reporting Person has designated as 19.99% of the shares of common stock outstanding.
Footnote F5
(Continued from footnote 4) A holder may reset that limitation to a lower percentage effective immediately, or to a higher percentage not exceeding 19.99% effective on the 61st day after written notice to the Issuer, and the limitation is automatically set at 9.99% at any time the holder's beneficial ownership is 9.00% or less of the outstanding common stock.
Footnote F6
Represents the number of shares of the Issuer's common stock underlying 2,074 shares of Issuer Preferred Stock received by the Reporting Person in the Merger in exchange for the shares of Pre-Merger Korsana's Series Seed Preferred Stock ("Korsana Series Seed Preferred Stock") held by the Reporting Person prior to the Merger. Each share of Korsana Series Seed Preferred Stock held at the Effective Time was exchanged for 0.0002074 shares of Issuer Preferred Stock.
Footnote F7
The pre-funded warrants to purchase shares of the Issuer's common stock (the "Issuer Pre-Funded Warrants") have no expiration date and are exercisable at any time and from time to time on or after the date of issuance. A holder may not exercise the Issuer Pre-Funded Warrants to the extent that, immediately prior to or following the exercise, the holder, together with its affiliates and any other persons whose beneficial ownership would be aggregated with the holder's for purposes of Section 13(d) of the Securities Exchange Act of 1934, would beneficially own shares of common stock in excess of the maximum percentage applicable to such holder, which the Reporting Person has elected to be 19.99% of the shares of common stock issued and outstanding following the exercise.
Footnote F8
(Continued from footnote 7) A holder may increase or decrease that maximum percentage by written notice to the Issuer, provided that it may not exceed 19.99% and that any increase is not effective until the 61st day after the notice is delivered to the Issuer.
Footnote F9
Represents the number of Issuer Pre-Funded Warrants received by the Reporting Person in the Merger in exchange for pre-funded warrants to purchase shares of Pre-Merger Korsana's common stock (the "Korsana Pre-Funded Warrants") held by the Reporting Person prior to the Merger. Each Korsana Pre-Funded Warrant held at the Effective Time was exchanged for 0.2074 Issuer Pre-Funded Warrants.
SEC remarks
Exhibit 24 - Power of Attorney Fairmount Funds Management LLC, Fairmount Healthcare Fund II L.P. and Fairmount Healthcare Co-Invest VI L.P. may each be deemed a director by deputization of the Issuer by virtue of the fact that Tomas Kiselak serves on the board of directors of the Issuer and is a manager of Fairmount Funds Management LLC.