Mirum Pharmaceuticals, Inc.

false 0001759425 0001759425 2026-05-12 2026-05-12 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 12, 2026 Mirum Pharmaceuticals, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38981 83-1281555 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS Employer Identification No.) 989 East Hillsdale Boulevard Suite 300 Foster City , California 94404 (Address of Principal Executive Offices) (Zip Code) Registrant’s Telephone Number, Including Area Code: (650) 667-4085 N/A (Former Name or Former Address, if Changed Since Last Report) Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common stock, par value $0.0001 per share MIRM Nasdaq Global Market Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Item 1.01 Entry Into a Material Definitive Agreement. Indenture and Notes On May 15, 2026, Mirum Pharmaceuticals, Inc. (the “Company”) issued $690.0 million aggregate principal amount of its 0.00% Convertible Senior Notes due 2032 (the “Notes”), which includes the full exercise of the initial purchasers’ option to purchase up to an additional $90.0 million aggregate principal amount of Notes. The Notes were issued pursuant to, and are governed by, an indenture (the “Indenture”), dated as of May 15, 2026, between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”). The Notes are the Company’s senior, unsecured obligations. The Notes will not bear regular interest, and the principal amount of the notes will not accrete. The Notes will mature on June 1, 2032, unless earlier converted, redeemed or repurchased. Noteholders may convert all or any portion of their Notes at their option only in the following circumstances: (i) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on September 30, 2026, if the last reported sale price per share of the Company’s common stock, $0.0001 par value per share (the “common stock”), exceeds 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (ii) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) if the trading price per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (iii) upon the occurrence of certain corporate events or distributions on the Company’s common stock, as described in the Indenture; (iv) if the Company calls such Notes for redemption; and (v) at any time from, and including, March 1, 2032 until the close of business on the second scheduled trading day immediately before the maturity date. The Company will settle conversions by paying or delivering, as applicable, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at its election, based on the applicable conversion rate(s). The initial conversion rate is 7.1971 shares of common stock per $1,000 principal amount of Notes, which represents an initial conversion price of approximately $138.94 per share, and is subject to adjustment upon the occurrence of certain events as described in the Indenture. If a “Make-Whole Fundamental Change” (as defined in the Indenture) occurs, then the Company will in certain circumstances increase the conversion rate for a specified period of time. The Company may not redeem the Notes at its option at any time before June 6, 2029. The Notes will be redeemable, in whole or in part (subject to the “Partial Redemption Limitation” (as defined in the Indenture)), at the Company’s option at any time, and from time to time, on a redemption date on or after June 6, 2029 and, in the case of any partial redemption, on or before the 30th scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the Notes to be redeemed, plus accrued and unpaid special interest and additional interest, if any, to, but excluding, the redemption date, but only if (i) the Notes are “Freely Tradeable” (as defined in the Indenture) as of the date the Company sends the related redemption notice and all accrued and unpaid additional interest, if any, has been paid in full as of the first interest payment date occurring on or before the date the Company sends such notice; and (ii) the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price on (1) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends such redemption notice; and (2) the trading day immediately before the date the Company sends such notice. In addition, calling any Note for redemption will constitute a Make-Whole Fundamental Change with respect to that Note, in which case the conversion rate applicable to the conversion of that Note will be increased in certain circumstances if it is converted after it is called for redemption and on or before the second business day immediately before the related redemption date. Pursuant to the Partial Redemption Limitation, the Company may not elect to redeem less than all of the outstanding Notes unless at least $75.0 million aggregate principal amount of Notes are outstanding and not subject to redemption as of the time the Company sends the related redemption notice. If a “Fundamental Change” (as defined in the Indenture) occurs, then, subject to limited exceptions as described in the Indenture, noteholders may require the Company to repurchase their Notes at a cash repurchase price equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid special interest and additional interest, if any, to, but excluding, the fundamental change repurchase date. The definition of Fundamental Change includes certain business combination transactions involving the Company and certain de-listing events with respect to the Company’s common stock. The Notes have customary provisions relating to the occurrence of “Events of Default” (as defined in the Indenture), which include the following: (i) certain payment defaults on the Notes (which, in the case of a default in the payment of interest, if any, on the Notes, will be subject to a 30-day cure period); (ii) the Company’s fa