Mirum director granted DSUs and stock options

Mirum Pharmaceuticals director Patrick J. Heron received new equity awards as part of his compensation.

Rhea-AI Filing Summary

Mirum Pharmaceuticals director Patrick J. Heron received new equity awards as part of his compensation. He was granted 1,980 deferred stock units and 3,772 stock options, each option giving the right to buy one share of common stock at an exercise price of $101.00 per share.

The stock options and deferred stock units vest on the first anniversary of the grant date, and in any case will be fully vested by the date of Mirum’s 2027 annual stockholder meeting. Each vested deferred stock unit will be settled in common stock upon a change in control of Mirum or within 60 days after his separation from service. These are grants and not open‑market purchases or sales.

Insider Trade Summary

Grant/Award: 5,752 shares

Grant/Award 2 txns

Insider Heron Patrick J

Role Director

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

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

Footnotes (2)

1. F1. 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. F2. Each deferred 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. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

Key Figures

Deferred stock units granted: 1,980 units Stock options granted: 3,772 options Option exercise price: $101.00 per share +3 more

6 metrics

Deferred stock units granted 1,980 units Award to director Patrick J. Heron

Stock options granted 3,772 options Award to director Patrick J. Heron

Option exercise price $101.00 per share Stock Option (right to buy) grant

Option expiration date June 14, 2036 Expiration of stock option grant

Shares underlying DSUs 1,980 shares Each DSU represents one common share

Shares underlying options 3,772 shares Each option for one common share

Key Terms

Deferred Stock Units, Stock Option (right to buy), change in control, separation from service

4 terms

Deferred Stock Units financial

"Each deferred stock unit represents a contingent right to receive one share"

Deferred stock units are promises from a company to give an employee shares of stock at a future date, often after certain conditions are met or after leaving the company. They function like a form of delayed compensation, allowing employees to earn shares over time. For investors, they represent potential future ownership in the company, but do not provide immediate voting rights or dividends until the shares are actually received.

Stock Option (right to buy) financial

"Stock Option (right to buy) with an exercise price of $101.0000"

change in control financial

"paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control"

A "change in control" occurs when the ownership or management of a company shifts significantly, such as through a merger, acquisition, or sale of a large part of its assets. This change can impact how the company is run and may influence its future direction. For investors, it matters because it can affect the company's stability, strategy, and value, often signaling potential changes in investment risk or opportunity.

separation from service financial

"within 60 days following separation from service with the Issuer"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Mirum Pharmaceuticals (MIRM) report for Patrick J. Heron?

Mirum reported that director Patrick J. Heron received equity awards, including 1,980 deferred stock units and 3,772 stock options. These awards are part of his compensation and do not represent open-market share purchases or sales.

How many deferred stock units did Patrick J. Heron receive from Mirum Pharmaceuticals (MIRM)?

Patrick J. Heron received 1,980 deferred stock units. Each unit represents a contingent right to one share of Mirum common stock, subject to vesting conditions and payout triggers described in the award terms.

What are the terms of Patrick J. Heron’s stock options at Mirum Pharmaceuticals (MIRM)?

Heron was granted 3,772 stock options with an exercise price of $101.00 per share, expiring on June 14, 2036. The options vest on the first anniversary of the grant date or will be fully vested by Mirum’s 2027 annual stockholder meeting.

When do Patrick J. Heron’s deferred stock units at Mirum Pharmaceuticals (MIRM) vest and pay out?

The deferred stock units vest on the first anniversary of the grant date, or fully by the 2027 annual stockholder meeting. Once vested, they are paid in common stock upon a change in control or within 60 days after separation from service.

Do Patrick J. Heron’s Form 4 transactions for Mirum Pharmaceuticals (MIRM) involve buying or selling shares on the market?

The reported transactions are equity grants, not open-market trades. They consist of awarded deferred stock units and stock options granted at no purchase price, reflecting compensation rather than discretionary buying or selling.

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

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Accepted by SEC EDGAR 06/17/2026 - 08:30 PM EDT 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^*

Heron Patrick J

(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
Deferred 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 deferred 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. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

	/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)