 Nkarta Inc. said late Tuesday it raised 289.8 million in its recent public offering after underwriters exercised all their options for shares to cover overallotments. On Friday, the biotech company priced 16.1 million shares at 18 and offered underwriters options for an additional 2.1 million, but on the first day of trading, shares rocketed to a high of 58.69. In the meantime, shares have settled a bit, shedding 20 on Monday, and closing down 6.4 at 36.05 on Tuesday, for market cap of 1.1 billion. 