X0306 4 2019-09-06 0 0001759425 Mirum Pharmaceuticals, Inc. MIRM 0001614740 Peetz Christopher C/O MIRUM PHARMACEUTICALS, INC. 950 TOWER LANE, SUITE 1050 FOSTER CITY CA 94404 1 1 0 0 President and CEO Common Stock 2019-09-06 4 P 0 4750 10.9065 A 192250 I By The Peetz Family Trust Common Stock 2019-09-09 4 P 0 2000 10.90 A 194250 I By The Peetz Family Trust Common Stock 2019-09-09 4 P 0 2320 11.35 A 196570 I By The Peetz Family Trust The weighted average purchase price for the transaction reported was $10.90645, and the range of prices were between $10.45 and $11.20. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares purchased at each separate price will be provided. /s/ Jody Howe, Attorney-in-Fact 2019-09-10