Groupon said Daniel Henry, the finance chief of American Express, and Robert Bass, a vice chairman of Deloitte, will become directors, underscoring efforts to shore up investors' confidence in its accounting.

Henry was appointed on April 26 to replace Howard Schultz, chief executive of Seattle-based Starbucks, who stepped down.

Bass will stand for election at the June 19 shareholder meeting.

Bass will replace Kevin Efrusy, a partner at venture-capital firm Accel Partners, who won't stand for re-election.

Both new directors will serve on the audit committee, Chicago-based Groupon said Monday.

Groupon, an online coupon company, is responding to criticism that it misled investors after reporting a "material weakness" in financial controls and lower fourth-quarter revenue than previously stated.

The stock has dropped 42 percent since the March 30 announcement, through Monday, and Groupon officers, directors and underwriters were named in a lawsuit filed by investor Fan Zhang in Chicago federal court this month.

The company had been seeking to hire at least two new directors after the restatement of revenue, two people with knowledge of the matter said last week.