Disc Medicine (NASDAQ: IRON) COO exercises options and sells 300 shares

Rhea-AI Filing Summary

Disc Medicine Chief Operating Officer Jonathan Yu reported a small, pre-planned insider transaction in Disc Medicine, Inc. common stock. On June 26, 2026, he exercised stock options to acquire 300 shares of common stock at $13.50 per share, then sold 300 shares of common stock at an average price of $72.50 per share in an open-market transaction.

The filing notes these trades were executed under a previously adopted Rule 10b5-1 trading plan, indicating they were scheduled in advance rather than timed discretionarily. A related footnote explains that the option grant vests in 48 equal monthly installments starting from December 29, 2022, contingent on Yu’s continued service.

Insights

Equity compensation analyst

Routine option exercise and sale under a pre-set plan.

The Form 4 shows Disc Medicine’s COO Jonathan Yu exercising options for 300 shares at $13.50 and selling 300 shares at $72.50. This is a classic exercise-and-sell pattern that converts an existing option award into cash.

The filing specifies these trades occurred under a Rule 10b5-1 trading plan adopted on March 17, 2026. Such plans are arranged in advance, so the timing gives limited insight into management’s current view of the stock. The option grant itself vests monthly over four years starting December 29, 2022, reflecting standard long-term incentive design.

Insider Trade Summary 10b5-1

Net Seller: 300 shares ($21,750)

Net Sell 3 txns

Insider Yu Jonathan Yen-Wen

Role Chief Operating Officer

Sold 300 shs ($22K)

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy)	300	$0.00	--
Exercise	Common Stock	300	$13.50	$4K
Sale	Common Stock	300	$72.50	$22K

Holdings After Transaction: Stock Option (Right to Buy) — 23,847 shares (Direct, null); Common Stock — 54,624 shares (Direct, null)

Footnotes (1)

1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026. The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

Key Figures

Shares sold: 300 shares Sale price: $72.50 per share Options exercised: 300 shares +4 more

7 metrics

Shares sold 300 shares Common Stock sold in open-market transaction on June 26, 2026 at $72.50

Sale price $72.50 per share Average price for 300 common shares sold June 26, 2026

Options exercised 300 shares Common Stock acquired via option exercise at $13.50 on June 26, 2026

Option exercise price $13.50 per share Exercise price for Stock Option (Right to Buy) into common shares

10b5-1 plan adoption date March 17, 2026 Date COO adopted Rule 10b5-1 trading plan governing these trades

Option expiration December 28, 2032 Expiration date of the Stock Option (Right to Buy)

Vesting schedule 48 monthly installments Option vests monthly starting after December 29, 2022, contingent on service

Key Terms

Rule 10b5-1 trading plan, Stock Option (Right to Buy, vest in 48 equal monthly installments

3 terms

Rule 10b5-1 trading plan regulatory

"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026."

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

Stock Option (Right to Buy financial

"Stock Option (Right to Buy) with an exercise price of 13.5000 and expiration date of 2032-12-28."

vest in 48 equal monthly installments financial

"The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service."

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/30/2026 - 05:46 PM Accepted by SEC EDGAR 06/30/2026 - 05:45 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^*

Yu Jonathan Yen-Wen

(Last) (First) (Middle)

C/O DISC MEDICINE, INC.

321 ARSENAL STREET, SUITE 101

(Street)

WATERTOWN MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/26/2026

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 Stock	06/26/2026		M(1)		300	A	$13.5	54,624	D
Common Stock	06/26/2026		S(1)		300	D	$72.5	54,324	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)	$13.5	06/26/2026		M(1)			300	(2)	12/28/2032	Common Stock	300	$0	23,847	D

Explanation of Responses:

1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

2. The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

	By: /s/ Rahul Khara, as Attorney-in-Fact	06/30/2026
	** 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)

FAQ

What insider transaction did Disc Medicine (IRON) report for its COO?

Disc Medicine’s COO Jonathan Yu reported an option-related transaction involving 300 shares. He exercised stock options to acquire 300 shares at $13.50 each, then sold 300 common shares at an average price of $72.50 in an open-market trade.

Was the Disc Medicine (IRON) COO’s June 26, 2026 stock sale pre-planned?

Yes. The filing states the transactions were made under a Rule 10b5-1 trading plan adopted March 17, 2026. Such plans schedule trades in advance, reducing the significance of short-term market timing by the insider.

How many Disc Medicine (IRON) shares were sold and at what price?

The COO sold 300 shares of Disc Medicine common stock in an open-market transaction. The reported sale price was an average of $72.50 per share, according to the Form 4 insider trading report filed with the SEC.

At what price did the Disc Medicine (IRON) COO exercise stock options?

Jonathan Yu exercised stock options covering 300 shares of Disc Medicine common stock at an exercise price of $13.50 per share. This converted part of his stock option grant into actual shares that were then sold the same day.

How do the Disc Medicine (IRON) COO’s options vest over time?

The filing explains that the option grant vests in 48 equal monthly installments after December 29, 2022. Each monthly vesting is conditional on Jonathan Yu’s continued service with Disc Medicine on the applicable vesting dates.