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Mirum (MIRM) director converts 3,977 restricted stock units into common shares

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Mirum Pharmaceuticals director Laurent Fischer exercised restricted stock units into common shares. On May 29, 2026, 3,977 restricted stock units, each representing a right to receive one share of common stock, were converted into 3,977 shares of Mirum common stock. Following this derivative exercise, Fischer directly holds 10,727 shares of common stock. The restricted stock units represented a contingent right that vested on May 29, 2026.

Positive

  • None.

Negative

  • None.
Insider Fischer Laurent
Role null
Type Security Shares Price Value
Exercise Restricted Stock Units 3,977 $0.00 --
Exercise Common Stock 3,977 $0.00 --
Holdings After Transaction: Restricted Stock Units — 0 shares (Direct, null); Common Stock — 10,727 shares (Direct, null)
Footnotes (1)
  1. Each restricted stock unit represents a contingent right to receive one share of common stock (or its cash equivalent, at the discretion of the Issuer). Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and vests on May 29, 2026.
RSUs exercised 3,977 units Restricted stock units converted on May 29, 2026
Common shares received 3,977 shares Shares of Mirum common stock from RSU exercise
Holdings after transaction 10,727 shares Directly held Mirum common stock after exercise
Exercise transactions 1 transaction, 3,977 shares Derivative exercise count and shares in summary
Restricted Stock Units financial
"The transaction involved restricted stock units and common stock."
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.
derivative security financial
"The filing discloses an exercise or conversion of derivative securities."
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.
contingent right financial
"Each restricted stock unit represents a contingent right to receive one share of common stock."
vests financial
"Each restricted stock unit represents a contingent right to receive one share and vests on May 29, 2026."
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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*
Fischer Laurent
(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)
XDirector10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/29/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock05/29/2026M3,977A(1)10,727D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Units(1)05/29/2026M3,977 (2) (2)Common Stock3,977$00D
Explanation of Responses:
1. Each restricted stock unit represents a contingent right to receive one share of common stock (or its cash equivalent, at the discretion of the Issuer).
2. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and vests on May 29, 2026.
/s/ Judit Ryvkin, Attorney-in-Fact06/02/2026
** Signature of Reporting PersonDate
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 insider transaction did Mirum Pharmaceuticals (MIRM) report for Laurent Fischer?

Mirum Pharmaceuticals reported that director Laurent Fischer exercised 3,977 restricted stock units into 3,977 shares of common stock. This derivative exercise occurred on May 29, 2026, and increased his directly held Mirum common stock to a total of 10,727 shares.

How many Mirum (MIRM) shares does Laurent Fischer hold after this Form 4 filing?

After the reported transaction, Laurent Fischer directly holds 10,727 shares of Mirum common stock. This reflects the addition of 3,977 shares received upon exercising restricted stock units on May 29, 2026, as disclosed in the Form 4 insider transaction summary.

What was the size of the restricted stock unit exercise reported by Mirum (MIRM)?

The filing shows an exercise of 3,977 restricted stock units, each representing a contingent right to receive one share of common stock. These units vested on May 29, 2026 and were converted into 3,977 Mirum common shares held directly by Laurent Fischer.

What type of securities were involved in Laurent Fischer’s Mirum (MIRM) Form 4 transaction?

The transaction involved restricted stock units and common stock. Fischer exercised 3,977 restricted stock units, which each represented a contingent right to receive one share of Mirum common stock, resulting in the issuance of 3,977 common shares on May 29, 2026.

Did the Mirum (MIRM) Form 4 report any stock sales by Laurent Fischer?

The Form 4 does not report any stock sales by Laurent Fischer. It discloses an exercise or conversion of derivative securities, specifically 3,977 restricted stock units, into 3,977 shares of Mirum common stock, with no sell transactions indicated in the transaction summary.