Mirum (NASDAQ: MIRM) CMO logs RSU vesting and 6,911-share sale

Rhea-AI Filing Summary

Mirum Pharmaceuticals' Chief Medical Officer, Joanne Quan, reported equity award activity and a related share sale. On January 16, 2026, 12,500 restricted stock units vested and were converted into 12,500 shares of Mirum common stock at an exercise price of $0. Footnotes state that each unit represents one share and that one-third of the award vests on each anniversary of January 16, 2024 until fully vested after three years.

On January 20, 2026, Quan sold 6,911 shares of common stock at an average price of $90.2696 per share to cover tax withholding obligations tied to the vesting. After these transactions, she directly owned 11,305 shares of Mirum common stock and 12,500 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

OMB APPROVAL

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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^*

Quan Joanne

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF MEDICAL OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
01/16/2026

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	01/16/2026		M		12,500	A	(1)	18,216(2)	D
Common Stock	01/20/2026		S(3)		6,911	D	$90.2696	11,305	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
Restricted Stock Units	(1)	01/16/2026		M			12,500	(4)	(4)	Common Stock	12,500	$0	12,500	D

Explanation of Responses:

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

2. Includes 67 shares of common stock that were acquired by the Reporting Person on November 10, 2025, pursuant to the Issuer's Employee Stock Purchase Plan.

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

4. 1/3rd of the shares subject to the restricted stock units shall vest on each anniversary of January 16, 2024 (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	01/21/2026
	** Signature of Reporting Person	Date
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FAQ

What insider activity did Mirum Pharmaceuticals (MIRM) report for Joanne Quan?

Mirum Pharmaceuticals reported that Chief Medical Officer Joanne Quan had 12,500 restricted stock units vest into common stock on January 16, 2026, and she then sold 6,911 shares on January 20, 2026 to cover tax withholding obligations.

How many Mirum Pharmaceuticals (MIRM) shares did the CMO sell, and at what price?

On January 20, 2026, Chief Medical Officer Joanne Quan sold 6,911 shares of Mirum common stock at an average price of $90.2696 per share, as disclosed in the Form 4.

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

Following the reported transactions, Joanne Quan directly owned 11,305 shares of Mirum common stock and held 12,500 restricted stock units, each representing a right to receive one share.

What are the vesting terms of the Mirum Pharmaceuticals (MIRM) restricted stock units?

The footnotes state that one-third of the shares subject to the restricted stock units vest on each anniversary of January 16, 2024, so the entire award becomes fully vested on the three-year anniversary of that vesting commencement date.

Why did the Mirum Pharmaceuticals (MIRM) CMO sell shares on January 20, 2026?

A footnote explains that the 6,911 shares sold on January 20, 2026 were sold to cover tax withholding obligations associated with the vesting of restricted stock units.

What does each Mirum Pharmaceuticals (MIRM) restricted stock unit represent in this Form 4?

According to the disclosure, each restricted stock unit represents a contingent right to receive one share of Mirum Pharmaceuticals common stock upon vesting, with no exercise price.