Daniel Karlin - 25 Mar 2026 Form 4 Insider Report for Definium Therapeutics, Inc. (DFTX)

Reporting relationship: Chief Medical Officer
Issuer ticker: DFTX
Reported as of: 25 Mar 2026
Net transaction value: -$148,092
SEC form: 4
Accepted by SEC: 26 Mar 2026, 18:43:44 UTC
Prior SEC filing: 05 Feb 2026
Next SEC filing: 22 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/Mark Sullivan, Attorney-in-Fact for Dan Karlin

Key filing fact

Daniel Karlin filed Form 4 for Definium Therapeutics, Inc. (DFTX) on 26 Mar 2026.

Key facts

This page summarizes Daniel Karlin's Form 4 filing for Definium Therapeutics, Inc. (DFTX).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 26 Mar 2026, 18:43.

Change

Previous filing in this sequence was filed on 05 Feb 2026.
Current net transaction value: -$148,092.

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 (1)

CIK 0001897618 Primary reporting owner

Karlin Daniel

Relationship: Chief Medical Officer
Address: C/O DEFINIUM THERAPEUTICS, INC., ONE WORLD TRADE CENTER, SUITE 8500, NEW YORK
Signature: /s/Mark Sullivan, Attorney-in-Fact for Dan Karlin
Signature date: 26 Mar 2026

Reported non-derivative transactions

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

DFTX transaction

Common Shares

Sale

Transaction value: $148,092
Shares: -8,018
Change %: -1.9%
Price: $18.47
Shares after: 413,317
Date: 25 Mar 2026
Ownership: Direct
Footnotes: F1, F2, F3

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

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 3 footnotes

Footnote F1

Represents the number of Common Shares sold to satisfy withholding tax obligations in connection with the settlement of vested restricted stock units, pursuant to sell-to-cover elections under a Rule 10b5-1 plan adopted on June 14, 2022.

Footnote F2

The reported price is a weighted average sales price. These shares were sold in multiple transactions on March 25, 2026 at prices ranging from $18.36 to $18.80. The Reporting Person undertakes to provide 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 F3

Amount includes 1,586 shares acquired under the Definium Therapeutics, Inc. 2024 Employee Share Purchase Plan.