RA CAPITAL MANAGEMENT, L.P. - 08 Dec 2025 Form 4 Insider Report for Fulcrum Therapeutics, Inc. (FULC)

Reporting relationship: 10%+ Owner
Issuer ticker: FULC
Reported as of: 08 Dec 2025
Net transaction value: -$58,377,021
SEC form: 4
Accepted by SEC: 10 Dec 2025, 16:42:29 UTC
Prior SEC filing: 24 Nov 2025
Next SEC filing: 15 Dec 2025
Source filing: View source filing
Reporting owner signature: /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.

Key filing fact

RA CAPITAL MANAGEMENT, L.P. filed Form 4 for Fulcrum Therapeutics, Inc. (FULC) on 10 Dec 2025.

Key facts

This page summarizes RA CAPITAL MANAGEMENT, L.P.'s Form 4 filing for Fulcrum Therapeutics, Inc. (FULC).
3 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 10 Dec 2025, 16:42.

Change

Previous filing in this sequence was filed on 24 Nov 2025.
Current net transaction value: -$58,377,021.

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

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (4)

CIK 0001346824 Primary reporting owner

RA CAPITAL MANAGEMENT, L.P.

Relationship: 10%+ Owner
Address: 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.
Signature date: 10 Dec 2025

CIK 0001315082

RA Capital Healthcare Fund LP

Relationship: 10%+ Owner
Address: 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P.
Signature date: 10 Dec 2025

CIK 0001384859

Kolchinsky Peter

Relationship: 10%+ Owner
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ /s/ Peter Kolchinsky, individually
Signature date: 10 Dec 2025

CIK 0001619841

Shah Rajeev M.

Relationship: 10%+ Owner
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Rajeev Shah, individually
Signature date: 10 Dec 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

FULC transaction

Common Stock

Sale

Transaction value: $18,355,677
Shares: -1,377,020
Change %: -13%
Price: $13.33
Shares after: 8,852,079
Date: 08 Dec 2025
Ownership: See footnotes
Footnotes: F1, F2, F3

FULC transaction

Common Stock

Sale

Transaction value: $38,647,349
Shares: -2,706,397
Change %: -31%
Price: $14.28
Shares after: 6,145,682
Date: 08 Dec 2025
Ownership: See footnotes
Footnotes: F2, F3, F4

FULC transaction

Common Stock

Sale

Transaction value: $1,373,996
Shares: -91,722
Change %: -1.5%
Price: $14.98
Shares after: 6,053,960
Date: 08 Dec 2025
Ownership: See footnotes
Footnotes: F2, F3, F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.81 to $13.8099 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Footnote F2

RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.

Footnote F3

Held directly by the Fund.

Footnote F4

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.81 to $14.805 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Footnote F5

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.81 to $15.39 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.