Mirum (MIRM) CEO sells shares to cover taxes after RSU vesting

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. chief executive officer Christopher Peetz reported routine equity compensation activity and a related share sale. On January 21, 2026, 12,797 shares of common stock were acquired upon the vesting and settlement of restricted stock units, increasing his directly held common stock to 170,831 shares and his directly held restricted stock units to 25,593 units. On January 22, 2026, he sold 7,098 shares of common stock at $93.3252 per share, and the filing states these shares were sold to cover tax withholding obligations from the RSU vesting. After these transactions, he directly owns 163,733 shares of common stock and indirectly holds 187,500 shares of common stock through The Peetz Family Trust, in addition to the outstanding restricted stock units.

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

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

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^*

Peetz Christopher

(Last) (First) (Middle)

C/O MIRUM PHARMACEUTICALS, INC.

989 E HILLSDALE BLVD., SUITE 300

(Street)

FOSTER CITY CA 94404

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Mirum Pharmaceuticals, Inc. [ MIRM ]

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)
01/21/2026

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	01/21/2026		M		12,797	A	(1)	170,831	D
Common Stock	01/22/2026		S(2)		7,098	D	$93.3252	163,733	D
Common Stock								187,500	I	By The Peetz Family Trust

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
Restricted Stock Units	(1)	01/21/2026		M			12,797	(3)	(3)	Common Stock	12,797	$0	25,593	D

Explanation of Responses:

1. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock.

2. Shares sold to cover tax withholding obligations associated with the vesting of restricted stock units.

3. 1/3rd of the shares subject to the restricted stock units shall vest on each anniversary of January 21, 2025 (the "Vesting Commencement Date"), such that the entire award will be vested on the three-year anniversary of the Vesting Commencement Date.

	/s/ Judit Ryvkin, Attorney-in-Fact	01/23/2026
	** Signature of Reporting Person	Date
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FAQ

What insider transaction did Mirum (MIRM) CEO Christopher Peetz report?

Christopher Peetz, chief executive officer and director of Mirum Pharmaceuticals, Inc., reported the vesting of restricted stock units into 12,797 shares of common stock on January 21, 2026 and a subsequent sale of 7,098 shares of common stock on January 22, 2026.

How many Mirum (MIRM) shares did the CEO sell and at what price?

On January 22, 2026, the CEO sold 7,098 shares of Mirum Pharmaceuticals common stock at a price of $93.3252 per share, as reported in the Form 4.

Why were the Mirum (MIRM) shares sold in this Form 4 filing?

The filing explains that the 7,098 shares were sold to cover tax withholding obligations associated with the vesting of restricted stock units, rather than as an open-market discretionary sale of the full RSU vesting amount.

How many Mirum (MIRM) shares does the CEO own after these transactions?

Following the reported transactions, the CEO directly owns 163,733 shares of Mirum Pharmaceuticals common stock and indirectly holds an additional 187,500 shares through The Peetz Family Trust, as reflected in the Form 4.

What is the status of the Mirum (MIRM) restricted stock units in this Form 4?

The Form 4 shows that restricted stock units converted into 12,797 shares of common stock on January 21, 2026, and that 25,593 restricted stock units remain directly beneficially owned after the transaction. Each restricted stock unit represents a contingent right to receive one share of common stock.

How do the Mirum (MIRM) CEO’s remaining restricted stock units vest over time?

According to the footnote, one-third of the shares subject to the restricted stock units vest on each anniversary of January 21, 2025, so the entire award will be vested on the three-year anniversary of that vesting commencement date.