Mirum Pharmaceuticals Inc. (NASDAQ: MIRM) announced the pricing of $600 million in convertible senior notes due 2032 in a private placement to qualified institutional buyers. The notes carry a 0% interest rate and are scheduled to settle on May 15, 2026.

The company granted initial purchasers an option to buy an additional $90 million in notes within 13 days of issuance. Net proceeds are estimated at $583.8 million, or $671.6 million if the option is fully exercised, after deducting fees and expenses.

The notes will mature on June 1, 2032, with an initial conversion rate of 7.1971 shares per $1,000 principal amount, representing a conversion price of approximately $138.94 per share. This reflects a 30% premium over Mirum's stock price of $106.88 on May 12, 2026.

Mirum plans to use approximately $475 million of proceeds and issue about 3.2 million shares to exchange for $237.2 million of existing 4% convertible notes due 2029 through privately negotiated transactions. The remainder will fund general corporate purposes, including potential acquisitions.

The notes cannot be redeemed before June 6, 2029, and conversion rights are limited before March 1, 2032. After that date, holders may convert at any time until maturity. If a fundamental change occurs, noteholders can require Mirum to repurchase their notes at principal value plus accrued interest.

The company warned that hedge unwinding activities by holders of the 2029 notes could affect its stock price, though the magnitude and overall impact remain unpredictable. The securities have not been registered under federal securities laws.