BillionToOne Inc. shares jumped 67% in their debut after the molecular diagnostics company raised $273.1 million in an upsized initial public offering.

Shares of the Menlo Park, California-based firm opened at $100 each on Thursday in New York, versus an IPO price of $60 apiece. The offering of 4.55 million shares was increased from the 3.85 million shares marketed in a range of $49 to $55 each.