Mirum (MIRM) CMO exercises performance RSUs, sells 7,287 shares for tax

Rhea-AI Filing Summary

Mirum Pharmaceuticals chief medical officer Joanne Quan exercised performance-based stock awards and sold shares mainly to cover taxes. On March 15, 2026, she exercised 13,334 performance restricted stock units, receiving the same number of Mirum common shares at a $0 exercise price, leaving 6,666 units outstanding. On March 16, 2026, she sold 7,287 shares of common stock in an open-market transaction at an average price of $91.9779 per share to satisfy tax withholding obligations tied to the vesting. After these transactions, Quan directly owned 18,864 Mirum common shares. The remaining performance units are scheduled to vest with two-thirds on March 15, 2026 and one-third on March 15, 2027, as described in the filing.

Insider Trade Summary

Net Seller: 7,287 shares ($670,243)

Net Sell 3 txns

Insider Quan Joanne

Role CHIEF MEDICAL OFFICER

Sold 7,287 shs ($670K)

Type	Security	Shares	Price	Value
Sale	Common Stock	7,287	$91.9779	$670K
Exercise	Performance Restricted Stock Units	13,334	$0.00	--
Exercise	Common Stock	13,334	$0.00	--

Holdings After Transaction: Common Stock — 18,864 shares (Direct); Performance Restricted Stock Units — 6,666 shares (Direct)

Footnotes (1)

1. Each performance restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. Shares sold to cover tax withholding obligations associated with the vesting of the performance restricted stock units. The shares vest as follows: 2/3 of the shares vest on March 15, 2026 and 1/3 of the shares vest on March 15, 2027.

Form 4 Insider Transactions: What Each Field Means →

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)
03/15/2026

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	03/15/2026		M		13,334	A	(1)	26,151	D
Common Stock	03/16/2026		S(2)		7,287	D	$91.9779	18,864	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
Performance Restricted Stock Units	(1)	03/15/2026		M			13,334	(3)	(3)	Common Stock	13,334	$0	6,666	D

Explanation of Responses:

1. Each performance 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 the performance restricted stock units.

3. The shares vest as follows: 2/3 of the shares vest on March 15, 2026 and 1/3 of the shares vest on March 15, 2027.

	/s/ Judit Ryvkin, Attorney-in-Fact	03/17/2026
	** 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).
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FAQ

What did Mirum Pharmaceuticals (MIRM) CMO Joanne Quan report in this Form 4?

Joanne Quan reported exercising performance restricted stock units into 13,334 Mirum common shares, then selling 7,287 shares. The sale was to cover tax withholding obligations from the vesting, leaving her with 18,864 directly owned shares after the transactions.

How many Mirum (MIRM) shares did Joanne Quan sell and at what price?

Joanne Quan sold 7,287 shares of Mirum common stock at an average price of $91.9779 per share. According to the filing, these shares were sold specifically to cover tax withholding obligations related to the vesting of performance restricted stock units.

What performance restricted stock units did Mirum CMO Joanne Quan exercise?

Joanne Quan exercised 13,334 performance restricted stock units, each representing a right to receive one Mirum common share. The exercise was at a $0 price, converting the units into 13,334 shares and leaving 6,666 performance units outstanding after the reported transaction.

How many Mirum (MIRM) shares does Joanne Quan hold after these transactions?

Following the reported Form 4 transactions, Joanne Quan directly owns 18,864 shares of Mirum common stock. This figure reflects the net position after exercising 13,334 performance units into shares and selling 7,287 shares to satisfy related tax withholding obligations.

Why were Mirum (MIRM) shares sold in Joanne Quan’s Form 4?

The shares were sold to cover tax withholding obligations tied to the vesting of performance restricted stock units. The filing states that the 7,287 Mirum common shares sold were specifically used to satisfy these tax requirements rather than representing a discretionary open-market liquidation.

What is the vesting schedule for Joanne Quan’s Mirum performance stock units?

The filing explains that two-thirds of the performance restricted stock units vest on March 15, 2026, and one-third on March 15, 2027. The 13,334 units exercised in this Form 4 correspond to the portion that vested on March 15, 2026 under this schedule.