aibioMirum prices $600 million of 0% convertible notes and refinances 2029 debt
Tickers MIRM
The notes carry no interest and convert at about $138.94 a share, a 30% premium to the May 12 price. Mirum swapped $237.2 million of 4% notes due 2029 for cash and shares.
Key facts
- Company
- Mirum Pharmaceuticals, Inc. (NASDAQ: MIRM)
- News type
- Debt Financing
- Primary source
- Mirum Pharmaceuticals (press release in Form 8-K)
Mirum Pharmaceuticals said on May 12 that it priced a $600.0 million offering of 0.00% convertible senior notes due 2032 in a private placement to qualified institutional buyers. The notes were set to settle on May 15, and the initial purchasers had a 13-day option to purchase up to $90.0 million more.
The company later reported that it had issued $690.0 million in total, which includes the full exercise of the purchasers' option. The notes pay no regular interest, and the principal does not accrete.
The details
The notes mature on June 1, 2032, unless converted, redeemed or repurchased earlier. The initial conversion price is about $138.94 per share, a premium of roughly 30.0% over the last reported sale price of $106.88 on May 12. Mirum cannot redeem the notes at its election before June 6, 2029. Holders can convert only in certain circumstances before March 1, 2032, and Mirum can settle conversions in cash, shares or a mix.
Part of the proceeds went to a refinancing. In privately negotiated exchanges, Mirum expected to use about $475.0 million of the proceeds and issue 3,220,529 shares in exchange for about $237.2 million of its 4.00% convertible notes due 2029. The 8-K says a maximum of 6,455,778 shares could be issued on conversion of the new notes, based on the maximum conversion rate of 9.3562 shares per $1,000.
The second-quarter report states that Mirum settled $237.2 million of the 2029 notes, about 75% of the then-outstanding amount. Mirum said it would use the remaining proceeds for general corporate purposes, which may include acquiring complementary products, technologies, intellectual property or businesses.
Context
The financing arrived days after two data releases. On April 27, Mirum had reported phase 2b results for brelovitug in hepatitis delta, and on May 4 it announced that the primary endpoint was met in the phase 2b VISTAS study of volixibat in PSC.
Mirum had $391.4 million of cash and investments at the end of 2025.
What it means for investors
Zero-coupon converts carry no regular interest but cost shareholders in a different way. If the stock trades above the $138.94 conversion price, holders may convert and existing shareholders are diluted, and the principal is due in June 2032 if the notes do not convert.
The exchange retired about 75% of the 4.00% notes then outstanding. The 8-K also shows the trade-off: more than 3.2 million shares were issued in the exchange.
The filing lists acquisitions among the possible uses of the remaining proceeds, which could include complementary products, technologies, intellectual property or businesses. Mirum named no target.
What to watch
Mirum has dated clinical readouts ahead, including AZURE-4 in the fourth quarter of 2026 and VANTAGE in the first quarter of 2027. The company cannot redeem the notes before June 6, 2029.