Mirum (MIRM) director Michael G. Grey awarded RSUs and $101 stock options

Rhea-AI Filing Summary

GREY MICHAEL G reported acquisition or exercise transactions in this Form 4 filing.

Mirum Pharmaceuticals director Michael G. Grey received new equity compensation awards. On June 15, 2026, he was granted 1,980 restricted stock units, each representing a right to receive one share of common stock, and 3,772 stock options exercisable at $101.00 per share.

Both the RSUs and options are scheduled to vest on the first anniversary of the grant date, but will in any case be fully vested on the date of Mirum’s 2027 annual stockholder meeting. After these grants, Grey directly holds 1,980 RSUs and 3,772 options, with the options expiring on June 14, 2036.

Insights

Equity Compensation Analyst

Routine director equity grants increase alignment but don’t signal trading views.

Director Michael G. Grey received 1,980 RSUs and 3,772 stock options with a $101.00 exercise price as part of his compensation. These awards are derivative acquisitions (code A), not open-market purchases or sales, and therefore carry limited information about his near-term view on the stock.

Vesting is time-based, occurring on the first anniversary of the grant or, at the latest, at the 2027 annual stockholder meeting. The options expire in 2036, indicating a long-dated incentive structure. Future company filings may show how much of these awards ultimately vest and whether any shares are later sold.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider GREY MICHAEL G

Role null

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	3,772	$0.00	--
Grant/Award	Restricted Stock Units	1,980	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 3,772 shares (Direct, null); Restricted Stock Units — 1,980 shares (Direct, null)

Footnotes (1)

1. The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

Key Figures

RSU grant: 1,980 units Option grant: 3,772 options Option exercise price: $101.00 per share +3 more

6 metrics

RSU grant 1,980 units Restricted Stock Units granted June 15, 2026

Option grant 3,772 options Stock options granted June 15, 2026

Option exercise price $101.00 per share Conversion/exercise price of stock options

Option expiration June 14, 2036 Expiration date of stock options

Underlying shares (options) 3,772 shares Common stock underlying granted options

Underlying shares (RSUs) 1,980 shares Common stock underlying granted RSUs

Key Terms

Restricted Stock Units, Stock Option, exercise price, annual stockholder meeting, +1 more

5 terms

Restricted Stock Units financial

"The 1,980 restricted stock units each represent a contingent right to receive one share"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Stock Option financial

"3,772 stock options with a $101.00 exercise price expiring on June 14, 2036"

A stock option is a contract that gives you the right to buy or sell a company's stock at a specific price within a certain time frame. People use them to potentially make money if the stock's price moves favorably or to protect against losses. It's like holding a coupon that can be used to buy or sell stock at a set price later on.

exercise price financial

"The 3,772 stock options have an exercise price of $101.00 per share"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

annual stockholder meeting financial

"Awards will be fully vested on the date of the Issuer's 2027 annual stockholder meeting"

An annual stockholder meeting is a yearly gathering where a company's owners (shareholders) receive updates on performance, vote on key issues like board members, executive pay and major corporate plans, and ask questions of management. Think of it as a company town hall where choices about oversight and direction are decided; outcomes can affect management accountability, corporate strategy and ultimately the value and risks of investors’ shares.

vest financial

"Both the RSUs and options vest on the first anniversary of the grant date"

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/17/2026 - 08:30 PM Accepted by SEC EDGAR 06/17/2026 - 08:30 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).

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^*

GREY MICHAEL G

(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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/15/2026

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

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
Stock Option (right to buy)	$101	06/15/2026		A		3,772		(1)	06/14/2036	Common Stock	3,772	$0	3,772	D
Restricted Stock Units	(2)	06/15/2026		A		1,980		(2)	(2)	Common Stock	1,980	$0	1,980	D

Explanation of Responses:

1. The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

2. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

	/s/ Doug Sheehy, Attorney-in-Fact	06/17/2026
	** 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).
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)

FAQ

What equity awards did Michael G. Grey receive in Mirum Pharmaceuticals (MIRM) Form 4?

Michael G. Grey received 1,980 restricted stock units and 3,772 stock options from Mirum Pharmaceuticals as equity compensation. Each RSU equals one common share, and the options carry a $101.00 per-share exercise price, all held directly after the grants.

When do Michael G. Grey’s new Mirum (MIRM) RSUs and options vest?

Both the 1,980 RSUs and 3,772 stock options vest on the first anniversary of the grant date. The footnotes state they will in any case be fully vested on the date of Mirum Pharmaceuticals’ 2027 annual stockholder meeting, providing a clear vesting backstop.

What is the exercise price and expiration date of Michael G. Grey’s Mirum (MIRM) stock options?

The 3,772 stock options granted to Michael G. Grey have an exercise price of $101.00 per share. According to the filing, these options expire on June 14, 2036, giving a long-term window for potential exercise if vesting conditions are met.

Are Michael G. Grey’s Mirum (MIRM) Form 4 transactions open-market buys or sells?

No, the Form 4 shows grant or award acquisitions coded as “A,” not open-market buys or sells. The transactions reflect compensation awards of RSUs and stock options, so they do not represent discretionary trading activity in Mirum Pharmaceuticals stock.

How many Mirum (MIRM) RSUs does Michael G. Grey hold after the reported grants?

After the reported grant, Michael G. Grey directly holds 1,980 restricted stock units tied to Mirum Pharmaceuticals common stock. Each RSU represents a contingent right to receive one share, subject to the described vesting schedule and the 2027 annual meeting milestone.

What underlying common stock is associated with Michael G. Grey’s Mirum (MIRM) derivatives?

Both derivative awards are linked to Mirum Pharmaceuticals common stock. The 1,980 restricted stock units each convert into one share, and the 3,772 stock options provide the right to buy common shares at $101.00 per share once vested and before expiration in 2036.