CRISPR Therapeutics AG (NASDAQ: CRSP) announced the pricing of $550 million aggregate principal amount of convertible senior notes due 2031 in a private offering to qualified institutional buyers. The offering was increased from the previously announced $350 million.

The notes carry an effective coupon of 1.125% for investors, though the company will pay 1.7308% to offset anticipated Swiss withholding taxes. Interest payments will occur semiannually on March 1 and September 1, beginning September 1, 2026. The notes mature on March 1, 2031.

Initial purchasers received an option to buy an additional $50 million of notes within 13 days of issuance. The sale is expected to close March 16, 2026, subject to customary conditions.

The conversion rate is set at 13.0617 common shares per $1,000 principal amount, equivalent to a conversion price of approximately $76.56 per share. This represents a 45% premium above the $52.80 closing price on March 10, 2026.

CRISPR Therapeutics cannot redeem the notes before March 6, 2029. After that date, the company may redeem notes if its stock price reaches at least 130% of the conversion price for 20 trading days within any 30-day period.

The company estimates net proceeds of approximately $536.3 million, or $585.2 million if purchasers exercise their full option. CRISPR Therapeutics plans to use proceeds for general corporate purposes.

The Zug, Switzerland-based gene editing company developed CASGEVY, described as the first approved CRISPR-based therapy for sickle cell disease and beta thalassemia.