Guardant Health Inc., a precision oncology company, has closed its IPO of 14,375,000 common shares at $19 each for gross proceeds of about $273.1 million.

The shares issued in the IPO include 1,875,000 additional shares of common stock sold pursuant to the full exercise of the underwriters' overallotment option, Guardant said in its Oct. 9 news release.

The healthcare equipment company's shares began trading on The Nasdaq Global Select Market on Oct. 4 under the ticker symbol GH.

J.P. Morgan Securities LLC and BofA Merrill Lynch acted as joint book-running managers, while Cowen and Co. LLC, Leerink Partners LLC and William Blair & Co. LLC acted as co-managers for the IPO.

Redwood City, Calif.-based Guardant Health offers noninvasive cancer diagnostics as well as liquid biopsy tests for advanced stage cancer.