Mirum Pharmaceuticals (MIRM) CEO exercises options and sells 40,000 shares

(Very High)

(Negative)

Form Type

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. reports that CEO Christopher Peetz exercised 40,000 employee stock options at $2.936 per share on August 11, 2025, receiving 40,000 common shares, and then sold 40,000 shares at $62.00 per share. A footnote notes the reported transaction occurred under a Rule 10b5-1 plan adopted on November 22, 2024, and that the stock option is fully vested with an expiration date of March 11, 2029. Following these transactions, Peetz holds 138,641 common shares directly and 208,570 shares indirectly through The Peetz Family Trust.

Insights

TL;DR: Insider transactions were pre-planned under a 10b5-1 plan and include an option exercise and an equal-sized block sale.

The transactions are explicitly reported as made pursuant to a Rule 10b5-1 trading plan, which indicates the trades were pre-scheduled and intended to provide an affirmative defense against insider trading claims. The CEO converted 40,000 vested options at a low exercise price ($2.936) and simultaneously sold 40,000 shares at $62.00. From a governance perspective, the use of a 10b5-1 plan reduces regulatory risk, while the sale materially reduces the CEO's direct share count by 40,000 shares. The presence of significant indirect ownership via a family trust (208,570 shares) suggests continued economic exposure.

TL;DR: Transaction structure is neutral; option exercise funded or converted into sale proceeds, with sustained indirect ownership.

The report shows an exercise of employee stock options that were fully vested and the subsequent sale of the same number of shares. The exercise price of $2.936 versus the sale price of $62.00 highlights a large realized spread per share, but the filing contains no information about the use of proceeds or market impact. After the transactions, direct holdings moved from 178,641 to 138,641 shares, while indirect holdings remain 208,570. On materiality, these are routine, pre-planned insider transactions rather than an unplanned, material governance event.

Insider Trade Summary

Exercise and Sale: 40,000 shares ($2.36M approx. pre-tax spread)

Exercise and Sale 4 txns

Insider Peetz Christopher

Role CHIEF EXECUTIVE OFFICER

Sold 40,000 shs ($2.48M)

Approx. gross sale proceeds $2.48M

Approx. exercise cost $117K

Approx. pre-tax spread $2.36M

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (right to buy)	40,000	$0.00	$0.00
Exercise	Common Stock	40,000	$2.936	$117K
Sale	Common Stock	40,000	$62.00	$2.48M
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (right to buy) — 158,487 shares (Direct); Common Stock — 138,641 shares (Direct); Common Stock — 208,570 shares (Indirect, By The Peetz Family Trust)

Footnotes (2)

F1. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on November 22, 2024.
F2. The stock option is fully vested.

Key Figures

Options Exercised: 40,000 shares Exercise Price: $2.936 per share Shares Sold: 40,000 shares +5 more

8 metrics

Options Exercised 40,000 shares Employee stock options exercised on August 11, 2025

Exercise Price $2.936 per share Conversion price for employee stock options into common stock

Shares Sold 40,000 shares Common stock sale on August 11, 2025

Sale Price $62.00 per share Per-share price for Mirum common stock sold by CEO

Direct Holdings After Transaction 138,641 shares Canonical post-transaction common stock held directly by Christopher Peetz

Indirect Trust Holdings 208,570 shares Common stock held indirectly through The Peetz Family Trust

Option Expiration Date March 11, 2029 Expiration of the fully vested employee stock option position

Rule 10b5-1 Plan Adoption November 22, 2024 Date the trading plan referenced in the footnote was adopted

Key Terms

Rule 10b5-1 Plan, Employee Stock Option, indirect ownership, The Peetz Family Trust, +1 more

5 terms

Rule 10b5-1 Plan regulatory

"Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person"

A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.

Employee Stock Option financial

"security_title: Employee Stock Option (right to buy)"

An employee stock option is a promise that lets a worker buy company shares later at a predetermined price, often after they stay for a certain period or meet performance goals — think of it like a coupon that locks in today's price for a future purchase. It matters to investors because options align employees’ incentives with company performance, can increase the number of shares outstanding (dilution) when exercised, and represent a compensation cost that affects reported profits and shareholder value.

indirect ownership financial

"ownership_type: indirect, nature_of_ownership: By The Peetz Family Trust"

The Peetz Family Trust financial

"nature_of_ownership: By The Peetz Family Trust"

fully vested financial

"A footnote notes that the stock option is fully vested."

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Accepted by SEC EDGAR 08/12/2025 - 07:57 PM

FAQ

What did Mirum Pharmaceuticals (MIRM) CEO Christopher Peetz report in this Form 4?

Christopher Peetz exercised 40,000 stock options and sold 40,000 common shares. The transactions occurred on August 11, 2025, and involved option exercise at $2.936 per share followed by a sale at $62.00 per share.

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

Peetz sold 40,000 shares of Mirum common stock at $62.00 per share. The sale followed an exercise of 40,000 employee stock options and was reported as part of the August 11, 2025 transactions.

What stock options did Christopher Peetz exercise in Mirum Pharmaceuticals (MIRM)?

Peetz exercised 40,000 fully vested employee stock options at $2.936 per share. The options converted into 40,000 shares of common stock and carry an expiration date of March 11, 2029, according to the filing.

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

After the reported transactions, Peetz holds 138,641 shares directly. He also has 208,570 Mirum common shares held indirectly through The Peetz Family Trust, reflecting both direct and trust-based ownership.

Were the Mirum Pharmaceuticals (MIRM) CEO’s transactions made under a Rule 10b5-1 plan?

A footnote states the reported transaction occurred under a Rule 10b5-1 plan. The plan was adopted by Christopher Peetz on November 22, 2024, indicating the trades were executed pursuant to a pre-arranged trading arrangement.

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).

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

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)
08/11/2025

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/11/2025		M		40,000	A	$2.936	178,641	D
Common Stock	08/11/2025		S⁽¹⁾		40,000	D	$62	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Employee Stock Option (right to buy)	$2.936	08/11/2025		M			40,000	⁽²⁾	03/11/2029	Common Stock	40,000	$0	158,487	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 stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	08/12/2025
	** 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.

Source: View Original Filing on SEC EDGAR