Disc Medicine (IRON) CEO reports option exercise and share sale

Rhea-AI Filing Summary

Disc Medicine, Inc.’s chief executive officer and director reported a series of equity transactions on December 11, 2025. On that date, the insider exercised stock options to acquire 40,000 shares of common stock at a price of $9.86 per share, then sold 40,000 common shares in multiple market trades at weighted average prices detailed in the footnotes.

The activity was carried out under a Rule 10b5-1 trading plan adopted on February 13, 2025. After these transactions, the insider directly beneficially owned 171,828 shares of Disc Medicine common stock and held 75,375 stock options that remain beneficially owned following the reported exercise.

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^*

Quisel John D

(Last) (First) (Middle)

C/O DISC MEDICINE, INC.

321 ARSENAL STREET, SUITE 101

(Street)

WATERTOWN MA 02472

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Disc Medicine, Inc. [ IRON ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
12/11/2025

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

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

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

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 Stock	12/11/2025		M(1)		40,000	A	$9.86	211,828	D
Common Stock	12/11/2025		S(1)		2,419	D	$90.973(2)	209,409	D
Common Stock	12/11/2025		S(1)		4,337	D	$92.2112(3)	205,072	D
Common Stock	12/11/2025		S(1)		16,356	D	$92.9566(4)	188,716	D
Common Stock	12/11/2025		S(1)		16,888	D	$93.6493(5)	171,828	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
Stock Option (Right to Buy)	$9.86	12/11/2025		M(1)			40,000	(6)	09/13/2031	Common Stock	40,000	$0	75,375	D

Explanation of Responses:

1. The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on February 13, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $90.40 to $91.37, inclusive. The Reporting Person undertakes 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 ranges set forth in footnotes (2) through (5) to this Form 4.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $91.46 to $92.43, inclusive.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $92.46 to $93.44, inclusive.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $93.46 to $94.24, inclusive.

6. The shares underlying this option are fully vested and exercisable as of the date hereof.

	By: /s/ Rahul Khara, as Attorney-in-Fact	12/15/2025
	** 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.

FAQ

What insider transaction did Disc Medicine (IRON) report on this Form 4?

The filing shows that Disc Medicine’s chief executive officer and director exercised stock options for 40,000 common shares and sold 40,000 common shares in multiple trades on December 11, 2025.

At what prices were the Disc Medicine (IRON) shares sold by the insider?

The common shares were sold in several transactions at weighted average prices, including $90.973, $92.2112, $92.9566, and $93.6493 per share, with detailed price ranges provided in the footnotes.

What was the exercise price of the stock options used by the Disc Medicine (IRON) insider?

The insider exercised a stock option to purchase 40,000 shares of Disc Medicine common stock at an exercise price of $9.86 per share.

How many Disc Medicine (IRON) shares does the insider own after these transactions?

Following the reported transactions, the insider directly beneficially owned 171,828 shares of Disc Medicine common stock.

How many stock options does the Disc Medicine (IRON) insider still hold?

After the option exercise reported, the insider beneficially owned 75,375 stock options, as shown in the derivative securities table.

Were the Disc Medicine (IRON) trades made under a Rule 10b5-1 plan?

Yes. The transactions were effected pursuant to a Rule 10b5-1 trading plan that was adopted on February 13, 2025, as stated in the footnotes.