[Form 4] Mirum Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Insider transactions by a company director: Mirum Pharmaceuticals director Saira Ramasastry exercised a stock option and sold the resulting shares on 09/08/2025. The reporting shows an exercise (code M) of 17,000 shares at a conversion/exercise price of $23.51, followed the same day by a sale (code S) of 17,000 common shares at a weighted average sale price of $77.042178 (range: $76.835–$77.29). The derivative disclosure notes the option is fully vested. The Form 4 was signed by an attorney-in-fact on behalf of the reporting person.

Insights

Securities Analyst

TL;DR: Director exercised a vested option and sold all acquired shares the same day, yielding a material realized gain per share.

The filing documents a standard option exercise (exercise price $23.51) and immediate disposition of 17,000 shares at a weighted average sale price of $77.042178. This represents a clear, reportable insider liquidity event without additional context on intent. The disclosure includes the sale price range and offers provision for providing per-price quantities on request, which supports transparency.

Corporate Governance Expert

TL;DR: Routine, compliant Section 16 filing showing a director's vested-option exercise and contemporaneous sale; fully vested option disclosed.

The Form 4 identifies the reporting person as a director and confirms the stock option is fully vested. The document is properly signed by an attorney-in-fact and supplies the weighted-average sale price plus the range, meeting common disclosure expectations. No amendment or additional linked arrangements are disclosed in this filing.

Insider Trade Summary

Exercise and Sale: 17,000 shares ($-400K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Ramasastry Saira

Role Director

Sold 17,000 shs ($0.00)

Approx. gross sale proceeds $0.00

Approx. exercise cost $400K

Approx. pre-tax spread $-400K

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	17,000	$0.00	$0.00
Exercise	Common Stock	17,000	$23.51	$400K
Sale	Common Stock	17,000	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 17,000 shares (Direct); Common Stock — 0 shares (Direct)

Footnotes (2)

1. F1. The weighted average sale price for the transaction reported was $77.042178, and the range of prices were between $76.835 and $77.29. 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.
2. F2. The stock option is fully vested.

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Form 4 Insider Transactions: What Each Field Means →

Accepted by SEC EDGAR 09/10/2025 - 05:50 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^*

Ramasastry Saira

(Last) (First) (Middle)

C/O MIRUM PHARMACEUTICALS, INC.

989 E HILLSDALE BLVD., SUITE 300

(Street)

FOSTER CITY CA 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
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/08/2025

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/08/2025		M		17,000	A	$23.51	17,000	D
Common Stock	09/08/2025		S		17,000	D	(1)	0	D

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)	$23.51	09/08/2025		M			17,000	(2)	06/01/2032	Common Stock	17,000	$0	17,000	D

Explanation of Responses:

1. The weighted average sale price for the transaction reported was $77.042178, and the range of prices were between $76.835 and $77.29. 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.

2. The stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	09/10/2025
	** 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.