Mirum director exercises and sells 2,000 shares

Mirum Pharmaceuticals director Saira Ramasastry exercised options and sold the resulting shares in a planned transaction.

Rhea-AI Filing Summary

Mirum Pharmaceuticals director Saira Ramasastry exercised options and sold the resulting shares in a planned transaction. On April 15, 2026, she exercised a stock option to acquire 2,000 shares of Mirum common stock at $23.51 per share, from a fully vested option. The same day, she sold 2,000 common shares in an open-market transaction at $96.90 per share, leaving 0 shares of common stock reported as directly owned after the sale. The filing notes the activity occurred under a Rule 10b5-1 trading plan adopted on September 18, 2025, indicating the trades were pre-arranged.

Insider Trade Summary 10b5-1

Exercise and Sale: 2,000 shares ($147K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Ramasastry Saira

Role Director

Sold 2,000 shs ($194K)

Approx. gross sale proceeds $194K

Approx. exercise cost $47K

Approx. pre-tax spread $147K

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	2,000	$0.00	$0.00
Exercise	Common Stock	2,000	$23.51	$47K
Sale	Common Stock	2,000	$96.90	$194K

Holdings After Transaction: Stock Option (right to buy) — 2,000 contracts (Direct); Common Stock — 0 shares (Direct)

Footnotes (2)

1. F1. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on September 18, 2025.
2. F2. The stock option is fully vested.

Key Figures

Options exercised: 2,000 shares Exercise price: $23.51 per share Shares sold: 2,000 shares +3 more

6 metrics

Options exercised 2,000 shares Stock option exercise on April 15, 2026

Exercise price $23.51 per share Strike price of stock option exercised

Shares sold 2,000 shares Open-market sale on April 15, 2026

Sale price $96.90 per share Price for common stock sale

Post-transaction holdings 0 shares Common stock directly owned after sale

10b5-1 plan adoption date September 18, 2025 Date trading plan was adopted

Key Terms

Rule 10b5-1 Plan, Stock Option (right to buy), derivative security, 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"

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.

Stock Option (right to buy) financial

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

derivative security financial

"transaction_code_description: "Exercise or conversion of derivative security""

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

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.

fully vested financial

"The stock option is fully vested."

FAQ

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

What insider transaction did Mirum Pharmaceuticals (MIRM) director Saira Ramasastry report?

Director Saira Ramasastry reported exercising stock options for 2,000 Mirum shares and selling all 2,000 shares. The exercise price was $23.51 per share and the shares were sold at $96.90 per share in an open-market transaction.

At what prices did Saira Ramasastry exercise and sell Mirum (MIRM) shares?

She exercised options to acquire 2,000 Mirum shares at $23.51 per share, then sold 2,000 common shares at $96.90 per share. These actions occurred on April 15, 2026, as part of a pre-arranged trading plan.

How many Mirum Pharmaceuticals (MIRM) shares does Saira Ramasastry hold after this Form 4?

After the reported transactions, the Form 4 shows Saira Ramasastry directly owning 0 shares of Mirum common stock. The 2,000 shares acquired through option exercise were sold the same day, and no remaining derivative position is listed.

Was the Mirum (MIRM) insider sale by Saira Ramasastry under a Rule 10b5-1 plan?

Yes. The filing states the reported transaction occurred under a Rule 10b5-1 trading plan adopted by Saira Ramasastry on September 18, 2025. Such plans pre-schedule trades, reducing the significance of short-term market timing.

What type of derivative security did Saira Ramasastry exercise for Mirum (MIRM)?

She exercised a fully vested stock option covering 2,000 Mirum common shares at a $23.51 exercise price. The option, described as a “Stock Option (right to buy),” originally had an expiration date in June 2032 before being fully exercised.

How many Mirum (MIRM) shares did Saira Ramasastry sell in this insider transaction?

She sold 2,000 shares of Mirum common stock in an open-market transaction coded as an “S” sale. The shares were sold at $96.90 per share on April 15, 2026, immediately after exercising options for the same number of shares.

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

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Accepted by SEC EDGAR 04/16/2026 - 08:40 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).

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^*

Ramasastry Saira

(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)
04/15/2026

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
Common Stock	04/15/2026		M		2,000	A	$23.51	2,000	D
Common Stock	04/15/2026		S(1)		2,000	D	$96.9	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	04/15/2026		M			2,000	(2)	06/01/2032	Common Stock	2,000	$0	2,000	D

Explanation of Responses:

1. Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on September 18, 2025.

2. The stock option is fully vested.

	/s/ Judit Ryvkin, Attorney-in-Fact	04/16/2026
	** 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)