Mirum Pharma CEO exercises options, sells 30K shares

Mirum Pharmaceuticals’ CEO exercised options and sold 30,000 MIRM shares under a pre-arranged Rule 10b5-1 trading plan.

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. (MIRM) reported that Chief Executive Officer Christopher Peetz exercised fully vested stock options for 30,000 shares of common stock on September 1, 2026 at an exercise price of $2.936 per share, receiving 30,000 shares of common stock. On the same date, he sold 8,312 shares at a weighted average price of $98.08 per share and 21,688 shares at a weighted average price of $98.91 per share under a Rule 10b5-1 trading plan adopted on March 2, 2026. Following the option exercise, he held 58,487 stock options directly and 187,500 shares of common stock indirectly through The Peetz Family Trust.

Insider Trade Summary 10b5-1

Exercise and Sale: 30,000 shares ($2.87M approx. pre-tax spread)

Exercise and Sale 5 txns

Insider Peetz Christopher

Role CHIEF EXECUTIVE OFFICER

Sold 30,000 shs ($2.96M)

Approx. gross sale proceeds $2.96M

Approx. exercise cost $88K

Approx. pre-tax spread $2.87M

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (right to buy) F5	30,000	$0.00	$0.00
Exercise	Common Stock F1	30,000	$2.936	$88K
Sale	Common Stock F2, F3	8,312	$98.08	$815K
Sale	Common Stock F2, F4	21,688	$98.91	$2.15M
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (right to buy) — 58,487 contracts (Direct); Common Stock — 194,440 shares (Direct); Common Stock — 187,500 shares (Indirect, By The Peetz Family Trust)

Footnotes (5)

1. F1. Includes 131 shares of Common Stock that were acquired by the Reporting Person on May 10, 2026, pursuant to the Issuer's Employee Stock Purchase Plan.
2. F2. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.
3. F3. The weighted average sale price for the transaction reported was $98.08, and the range of prices were between $97.47 and $98.42. 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.
4. F4. The weighted average sale price for the transaction reported was $98.91, and the range of prices were between $98.49 and $99.38. 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.
5. F5. The stock option is fully vested.

Key Figures

Options exercised: 30,000 shares Option exercise price: $2.936 per share Shares sold at $98.08: 8,312 shares +5 more

8 metrics

Options exercised 30,000 shares Stock options for common stock exercised on September 1, 2026

Option exercise price $2.936 per share Exercise price for 30,000 options exercised on September 1, 2026

Shares sold at $98.08 8,312 shares Weighted average sale price of $98.08 per share on September 1, 2026

Shares sold at $98.91 21,688 shares Weighted average sale price of $98.91 per share on September 1, 2026

Total shares sold 30,000 shares Common stock sold on September 1, 2026 in two tranches

Remaining stock options 58,487 options Directly held options following the September 1, 2026 exercise

Indirectly held common shares 187,500 shares Common stock held by The Peetz Family Trust as of September 1, 2026

ESPP shares included 131 shares Shares acquired on May 10, 2026 under the Employee Stock Purchase Plan

Key Terms

Rule 10b5-1 Plan, weighted average sale price, Employee Stock Purchase Plan, fully vested

4 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.

weighted average sale price financial

"The weighted average sale price for the transaction reported was $98.08"

Employee Stock Purchase Plan financial

"acquired by the Reporting Person on May 10, 2026, pursuant to the Issuer's Employee Stock Purchase Plan"

An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.

fully vested financial

"The stock option is fully vested"

FAQ

What stock option activity did MIRM’s CEO report on this Form 4?

On September 1, 2026, Mirum Pharmaceuticals’ CEO Christopher Peetz exercised options for 30,000 shares of common stock at an exercise price of $2.936 per share, converting those options into an equivalent number of common shares.

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

On September 1, 2026, Christopher Peetz sold a total of 30,000 shares of Mirum Pharmaceuticals common stock, including 8,312 shares at a weighted average price of $98.08 per share and 21,688 shares at a weighted average price of $98.91 per share.

Were the MIRM share sales by the CEO made under a Rule 10b5-1 plan?

Yes. The filing states that the reported sales of Mirum Pharmaceuticals common stock occurred pursuant to a Rule 10b5-1 plan adopted by Christopher Peetz on March 2, 2026, indicating the trades followed a pre-arranged trading schedule.

What Mirum Pharmaceuticals holdings does the CEO report after these transactions?

After the reported option exercise, Christopher Peetz held 58,487 stock options directly and 187,500 shares of Mirum Pharmaceuticals common stock indirectly, held by The Peetz Family Trust as of September 1, 2026.

What is the status of the stock option exercised by the MIRM CEO?

The stock option exercised by Christopher Peetz on September 1, 2026 is described as fully vested, with an exercise price of $2.936 per share and an expiration date of March 11, 2029.

Does the Form 4 mention Mirum’s Employee Stock Purchase Plan?

Yes. The filing notes that the CEO’s reported common stock holdings include 131 shares acquired on May 10, 2026 under Mirum Pharmaceuticals’ Employee Stock Purchase Plan.

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

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 09/03/2026 - 06:54 PM Accepted by SEC EDGAR 09/03/2026 - 06:52 PM Learn about SEC filing dates

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 CALIFORNIA 94404

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	09/01/2026		M		30,000	A	$2.936	224,440(1)	D
Common Stock	09/01/2026		S(2)		8,312	D	$98.08(3)	216,128	D
Common Stock	09/01/2026		S(2)		21,688	D	$98.91(4)	194,440	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
Employee Stock Option (right to buy)	$2.936	09/01/2026		M			30,000	(5)	03/11/2029	Common Stock	30,000	$0	58,487	D

Explanation of Responses:

1. Includes 131 shares of Common Stock that were acquired by the Reporting Person on May 10, 2026, pursuant to the Issuer's Employee Stock Purchase Plan.

2. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

3. The weighted average sale price for the transaction reported was $98.08, and the range of prices were between $97.47 and $98.42. 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.

4. The weighted average sale price for the transaction reported was $98.91, and the range of prices were between $98.49 and $99.38. 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.

5. The stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	09/03/2026
	** 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).
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.
* Form 4: SEC 1474 (03-26)