Were the Mirum Pharmaceuticals (MIRM) CEO’s share sales pre-planned under Rule 10b5-1?

Yes. A footnote states the reported transactions occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026. Such plans pre-schedule trades, reducing the significance of trade timing as a discretionary decision.

Mirum Pharmaceuticals (MIRM) CEO logs option exercise and 30K-share sale

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. director and chief executive officer Christopher Peetz reported option exercises and share sales in the company’s stock. On June 1, 2026, he exercised stock options for 30,000 shares of common stock at an exercise price of $2.936 per share and sold 30,000 shares of common stock in multiple open-market transactions. The sales occurred at prices ranging from about $93.90 to $99.79 per share pursuant to a pre-arranged Rule 10b5-1 Plan adopted on March 2, 2026. Following these transactions, he holds 224,309 shares of common stock directly and 187,500 shares indirectly through The Peetz Family Trust, as well as 128,487 stock options outstanding.

Insider Trade Summary 10b5-1

Net Seller: 30,000 shares ($2,875,103)

Net Sell 9 txns

Insider Peetz Christopher

Role CHIEF EXECUTIVE OFFICER

Sold 30,000 shs ($2.88M)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (right to buy)	30,000	$0.00	--
Exercise	Common Stock	30,000	$2.936	$88K
Sale	Common Stock	2,602	$94.64	$246K
Sale	Common Stock	16,595	$95.34	$1.58M
Sale	Common Stock	6,926	$96.15	$666K
Sale	Common Stock	1,973	$97.56	$192K
Sale	Common Stock	1,021	$98.20	$100K
Sale	Common Stock	883	$99.66	$88K
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (right to buy) — 128,487 shares (Direct, null); Common Stock — 224,309 shares (Direct, null); Common Stock — 187,500 shares (Indirect, By The Peetz Family Trust)

Footnotes (1)

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026. The weighted average sale price for the transaction reported was $94.64, and the range of prices were between $93.90 and $94.895. 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. The weighted average sale price for the transaction reported was $95.34, and the range of prices were between $94.91 and $95.91. 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. The weighted average sale price for the transaction reported was $96.15, and the range of prices were between $95.92 and $96.8675. 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. The weighted average sale price for the transaction reported was $97.56, and the range of prices were between $96.98 and $97.94. 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. The weighted average sale price for the transaction reported was $98.20, and the range of prices were between $98.00 and $98.38. 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. The weighted average sale price for the transaction reported was $99.66, and the range of prices were between $99.55 and $99.79. 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. The stock option is fully vested.

Key Figures

Shares sold: 30,000 shares Sale price range: $93.90–$99.79 per share Options exercised: 30,000 shares +5 more

8 metrics

Shares sold 30,000 shares Total common stock sold in open-market transactions on June 1, 2026

Sale price range $93.90–$99.79 per share Price ranges from weighted-average sale footnotes

Options exercised 30,000 shares Employee stock options converted into common stock on June 1, 2026

Option exercise price $2.936 per share Exercise price for employee stock options

Direct common shares after 224,309 shares Direct Mirum common stock holding following reported transactions

Indirect trust shares 187,500 shares Common stock held indirectly via The Peetz Family Trust

Remaining stock options 128,487 options Employee stock options outstanding after the exercise

Rule 10b5-1 plan adoption date March 2, 2026 Date the CEO adopted the trading plan governing these sales

Key Terms

Rule 10b5-1 Plan, weighted average sale price, Employee Stock Option (right to buy), open-market sale, +1 more

5 terms

Rule 10b5-1 Plan regulatory

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

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 $94.64, and the range of prices were between $93.90 and $94.895."

Employee Stock Option (right to buy) financial

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

open-market sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

derivative exercise/conversion financial

"transaction_action: derivative exercise/conversion"

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Form 4 Insider Transactions: What Each Field Means →

06/02/2026 - 07:50 PM

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

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)
06/01/2026

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)
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	06/01/2026		M		30,000	A	$2.936	224,309	D
Common Stock	06/01/2026		S⁽¹⁾		2,602	D	$94.64⁽²⁾	221,707	D
Common Stock	06/01/2026		S⁽¹⁾		16,595	D	$95.34⁽³⁾	205,112	D
Common Stock	06/01/2026		S⁽¹⁾		6,926	D	$96.15⁽⁴⁾	198,186	D
Common Stock	06/01/2026		S⁽¹⁾		1,973	D	$97.56⁽⁵⁾	196,213	D
Common Stock	06/01/2026		S⁽¹⁾		1,021	D	$98.2⁽⁶⁾	195,192	D
Common Stock	06/01/2026		S⁽¹⁾		883	D	$99.66⁽⁷⁾	194,309	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)
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	06/01/2026		M			30,000	⁽⁸⁾	03/11/2029	Common Stock	30,000	$0	128,487	D

Explanation of Responses:

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

2. The weighted average sale price for the transaction reported was $94.64, and the range of prices were between $93.90 and $94.895. 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 weighted average sale price for the transaction reported was $95.34, and the range of prices were between $94.91 and $95.91. 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 $96.15, and the range of prices were between $95.92 and $96.8675. 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 weighted average sale price for the transaction reported was $97.56, and the range of prices were between $96.98 and $97.94. 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.

6. The weighted average sale price for the transaction reported was $98.20, and the range of prices were between $98.00 and $98.38. 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.

7. The weighted average sale price for the transaction reported was $99.66, and the range of prices were between $99.55 and $99.79. 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.

8. The stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	06/02/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

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

Christopher Peetz reported exercising stock options for 30,000 Mirum Pharmaceuticals shares and selling 30,000 shares in open-market transactions. The filing also updates his direct, indirect, and option holdings following these June 1, 2026 transactions.

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

The CEO sold 30,000 Mirum Pharmaceuticals common shares in several open-market trades. Weighted average prices in the footnotes show sale ranges between approximately $93.90 and $99.79 per share across the reported transactions on June 1, 2026.

What stock options did the Mirum Pharmaceuticals (MIRM) CEO exercise?

He exercised employee stock options covering 30,000 Mirum Pharmaceuticals common shares at an exercise price of $2.936 per share. After this exercise, the table shows 128,487 stock options remaining outstanding in his direct derivative holdings.

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

After the reported trades, he holds 224,309 Mirum Pharmaceuticals common shares directly. He also holds 187,500 additional common shares indirectly through The Peetz Family Trust, according to the ownership entries in the Form 4.

What is the indirect Mirum Pharmaceuticals (MIRM) holding reported for The Peetz Family Trust?

The filing lists an indirect ownership entry of 187,500 Mirum Pharmaceuticals common shares held by The Peetz Family Trust. This reflects shares attributed to Christopher Peetz through the trust, separate from his directly held common stock.