Definium CCO sells 2,867 shares for tax withholding

Definium Therapeutics, Inc. Chief Commercial Officer Wiley Matthew T. reported the sale of 2,867 Common Shares on June 25, 2026 at an average price of $45.03 per share.

Rhea-AI Filing Summary

Definium Therapeutics, Inc. Chief Commercial Officer Wiley Matthew T. reported the sale of 2,867 Common Shares on June 25, 2026 at an average price of $45.03 per share. According to the footnote, these shares were sold to satisfy withholding tax obligations tied to the settlement of vested restricted stock units under a sell-to-cover election.

The transaction was carried out pursuant to a pre-adopted Rule 10b5-1 trading plan dated May 29, 2025, indicating it was pre-planned rather than a discretionary trade. Following this tax-related sale, Wiley beneficially owns 174,633 Common Shares directly, so the number of shares sold represents a small portion of his overall holdings.

Insider Trade Summary 10b5-1

Net Seller: 2,867 shares

Net Sell 1 txn

Insider Wiley Matthew T.

Role Chief Commercial Officer

Sold 2,867 shs ($129K)

Type	Security	Shares	Price	Value
Sale	Common Shares	2,867	$45.03	$129K

Holdings After Transaction: Common Shares — 174,633 shares (Direct)

Footnotes (1)

1. 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 May 29, 2025.

Key Figures

Shares sold: 2,867 shares Sale price: $45.03 per share Shares owned after transaction: 174,633 shares +1 more

4 metrics

Shares sold 2,867 shares Common Shares sold on June 25, 2026

Sale price $45.03 per share Average price for 2,867 Common Shares

Shares owned after transaction 174,633 shares Direct Common Share holdings post-transaction

Rule 10b5-1 plan adoption date May 29, 2025 Plan governing sell-to-cover tax sale

Key Terms

withholding tax obligations, restricted stock units, sell-to-cover elections, Rule 10b5-1 plan

4 terms

withholding tax obligations financial

"sold to satisfy withholding tax obligations in connection with the settlement"

restricted stock units financial

"in connection with the settlement of vested restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

sell-to-cover elections financial

"pursuant to sell-to-cover elections under a Rule 10b5-1 plan"

Rule 10b5-1 plan regulatory

"under a Rule 10b5-1 plan adopted on May 29, 2025"

A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did DFTX report for Chief Commercial Officer Wiley Matthew T.?

Definium Therapeutics’ Chief Commercial Officer Wiley Matthew T. reported selling 2,867 Common Shares. The sale occurred at an average price of $45.03 per share to cover withholding taxes from vested restricted stock units under a sell-to-cover arrangement.

Why did Wiley Matthew T. sell 2,867 Definium Therapeutics (DFTX) shares?

The 2,867 DFTX shares were sold to satisfy withholding tax obligations arising from the settlement of vested restricted stock units. The filing explains this was executed through sell-to-cover elections, meaning the sale was driven by tax requirements, not a discretionary portfolio decision.

Was the DFTX insider share sale made under a Rule 10b5-1 trading plan?

Yes. The filing states the sell-to-cover transactions occurred pursuant to a Rule 10b5-1 trading plan adopted on May 29, 2025. Such plans pre-schedule trades, reducing the significance of trade timing as an indication of the insider’s current view of the stock.

How many Definium Therapeutics shares does Wiley Matthew T. hold after this Form 4 transaction?

After selling 2,867 shares, Wiley Matthew T. directly owns 174,633 Common Shares of Definium Therapeutics. This shows the tax-related sale represents a relatively small fraction of his total reported holdings, suggesting his overall equity exposure to the company remains substantial.

What price did the Definium Therapeutics (DFTX) insider shares sell for in this Form 4?

The reported sale price was $45.03 per share for the 2,867 Common Shares. This figure reflects the average price received in the open-market sale used to fund withholding tax obligations connected to the vesting and settlement of restricted stock units.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/26/2026 - 04:30 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Wiley Matthew T.

(Last) (First) (Middle)

C/O DEFINIUM THERAPEUTICS, INC.

ONE WORLD TRADE CENTER, SUITE 8500

(Street)

NEW YORK NEW YORK 10007

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Definium Therapeutics, Inc. [ DFTX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Commercial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/25/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Shares	06/25/2026		S(1)		2,867	D	$45.03	174,633	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. 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 May 29, 2025.

	/s/Mark Sullivan, Attorney-in-Fact for Matthew T. Wiley	06/26/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)