[Form 4] Mirum Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Christopher Peetz, Mirum Pharmaceuticals (MIRM) Chief Executive Officer and director, reported option exercise and a planned sale of shares on 08/07/2025. He acquired 40,000 common shares by exercise at a conversion/exercise price of $2.936 per share, and concurrently sold 40,000 common shares under a Rule 10b5-1 plan at a weighted average price of $55.251 (range $55.25–$55.485). The filing notes the 10b5-1 plan was adopted on November 22, 2024, and the related employee stock option is fully vested.

The report lists direct beneficial ownership figures shown after the transactions (reported as 178,641 and 138,641 shares in the non-derivative table) and an indirect holding of 208,570 shares held by The Peetz Family Trust. The filing was submitted by an attorney-in-fact.

Positive

• Exercise of fully vested options (40,000 shares at $2.936) provides clear disclosure of strike and vesting status
• Planned sale executed under a Rule 10b5-1 plan, with adoption date (11/22/2024) disclosed, indicating prearranged trading

Negative

• Insider sale of 40,000 shares reported, which is a material insider disposition investors may note
• Significant share movement (exercise plus sale) changes direct beneficial ownership reported in the filing

Insights

Securities Analyst

TL;DR: Routine insider option exercise and planned sale under a 10b5-1 plan; factual disclosure without new corporate guidance.

The filing documents a simultaneous exercise of 40,000 options at a strike of $2.936 and the sale of 40,000 shares at a weighted average of $55.251 executed under a 10b5-1 plan adopted on 11/22/2024. The option is noted as fully vested, and the report specifies both direct and indirect beneficial ownership amounts. From a market-impact perspective, this is a clear, prearranged insider disposition and an option exercise rather than an ad-hoc sale or change in corporate outlook.

Corporate Governance Expert

TL;DR: Disclosure appears complete for Section 16 purposes; transactions tied to a documented 10b5-1 plan and vested options.

The report identifies the reporting person as both CEO and a director and states the transaction was executed pursuant to a Rule 10b5-1 trading plan. The filing includes the weighted average sale price, price range, and notes the option is fully vested—key items for transparency. The presence of indirect holdings via The Peetz Family Trust is explicitly disclosed. No material non-disclosure or governance irregularity is evident from the filed information alone.

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^*

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)
08/07/2025

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	08/07/2025		M		40,000	A	$2.936	178,641	D
Common Stock	08/07/2025		S(1)		40,000	D	$55.251(2)	138,641	D
Common Stock								208,570	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
Employee Stock Option (right to buy)	$2.936	08/07/2025		M			40,000	(3)	03/11/2029	Common Stock	40,000	$0	198,487	D

Explanation of Responses:

1. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on November 22, 2024.

2. The weighted average sale price for the transaction reported was $55.251022, and the range of prices were between $55.25 and $55.485. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

3. The stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	08/08/2025
	** 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 did Mirum (MIRM) CEO Christopher Peetz report on Form 4?

He reported acquiring 40,000 shares by exercising options at $2.936 and selling 40,000 shares at a weighted average price of $55.251 on 08/07/2025.

Were these transactions part of a trading plan for MIRM insider Christopher Peetz?

Yes. The sale was executed pursuant to a Rule 10b5-1 plan adopted on November 22, 2024.

Is the exercised stock option vested for Mirum CEO Peetz?

Yes. The filing explicitly states the stock option is fully vested.

What beneficial ownership does the filing report for Christopher Peetz?

The filing lists reported direct beneficial ownership amounts after transactions as 178,641 and 138,641 (as shown in the non-derivative table) and an indirect holding of 208,570 shares via The Peetz Family Trust.

What price range and weighted average were reported for the share sale?

The weighted average sale price was $55.251022, with a reported range of $55.25 to $55.485.