Sec Form 3 Filing - Howe Jolanda @ Mirum Pharmaceuticals, Inc. - 2023-05-01

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Howe Jolanda 2. Issuer Name and Ticker or Trading Symbol Mirum Pharmaceuticals, Inc. [ MIRM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, Global Controller (Last) (First) (Middle) C/O MIRUM PHARMACEUTICALS, INC., 950 TOWER LANE, SUITE 1050 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2023 (Street) FOSTER CITY, CA94404 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 1,769 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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) $ 2.94 ( 1 ) 03/11/2029 Common Stock 57,900 D Stock Option (right to buy) $ 6.27 ( 2 ) 05/13/2029 Common Stock 50,000 D Stock Option (right to buy) $ 19.24 ( 3 ) 01/09/2030 Common Stock 25,000 D Stock Option (right to buy) $ 19.19 ( 4 ) 01/06/2031 Common Stock 25,000 D Stock Option (right to buy) $ 15.87 ( 5 ) 01/05/2032 Common Stock 22,500 D Stock Option (right to buy) $ 19.98 ( 6 ) 06/30/2032 Common Stock 18,750 D Stock Option (right to buy) $ 23.48 ( 7 ) 01/30/2033 Common Stock 21,250 D Restricted Stock Units ( 9 ) ( 8 ) ( 8 ) Common Stock 2,500 D Restricted Stock Units ( 9 ) ( 10 ) ( 10 ) Common Stock 3,125 D Restricted Stock Units ( 9 ) ( 11 ) ( 11 ) Common Stock 5,315 D Performance Restricted Stock Units ( 9 ) ( 12 ) ( 12 ) Common Tcok 1,563 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Howe Jolanda C/O MIRUM PHARMACEUTICALS, INC. 950 TOWER LANE, SUITE 1050 FOSTER CITY, CA94404 SVP, Global Controller Signatures /s/ Judit Ryvkin, Attorney-in-Fact 05/08/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )1/4th of the 62,500 shares originally subject to the option vested one year after February 28, 2019, and the balance of the shares vest in a series of 36 successive equal monthly installments at the end of each month thereafter. ( 2 )1/4th of the shares vested one year after April 12, 2019 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 3 )1/4th of the shares vested one year after January 10, 2020 (the "Vesting Commencement Date") and the balance of the shares v est in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 4 )1/4th of the shares vested one year after January 7, 2021 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 5 )1/4th of the shares vested one year after January 6, 2022 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 6 )1/4th of the shares vest one year after July 1, 2022 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 7 )1/4th of the shares vest one year after January 31, 2023 (the "Vesting Commencement Date) and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date. ( 8 )The restricted stock units vest in a series of three successive equal annual installments beginning January 6, 2023. 1,250 shares vested January 6, 2023 and the remaining 2,500 shares vest ratably on January 6, 2024 and January 6, 2025. ( 9 )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). ( 10 )The restricted stock units vest in a series of three successive equal annual installments beginning July 1, 2023. ( 11 )The restricted stock units vest in a series of three successive equal annual installments beginning January 31, 2024. ( 12 )On March 9, 2021, the reporting person was granted performance-based restricted stock units ("PSUs"), which vest upon the satisfaction of certain performance criteria. On September 29, 2021, such performance criteria were met. 1,562 shares subject to the PSUs vested on September 29, 2021, and 1,563 shares vest on June 30, 2023.

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.