South Korean e-commerce giant Coupang Inc.'s revenue surged to $4.21 billion in the March quarter, but its loss widened on higher costs in part tied to the company's initial public offering.

It was Coupang's first earnings report as a publicly traded company.

The Seoul-based company, backed by Japan's SoftBank Group Corp., reported a net loss of $295 million for the quarter. On a per-share basis, the loss was 68 cents a share.

Net revenue rose to $4.21 billion from $2.41 billion a year earlier.

Coupang ended the first quarter with more than 16 million active customers, up 21% from the year earlier, while net revenues per active customer rose 44% to $262, the company said.

Webcast and Conference Call

Coupang, Inc. will host a conference call to discuss quarter results on May 12, 2021 at 5:30 PM Eastern Daylight Time (May 13, 2021 at 6:30 AM Korea Standard Time). A live webcast of the conference call will be available on our Investor Relations website, ir.aboutcoupang.com, and a replay of the conference call will be available for at least three months. This press release, including the reconciliations of certain non-GAAP measures to their nearest comparable U.S. GAAP measures, is also available on that site.

Write to Maria Armental at maria.armental@wsj.com