NEW YORK ( TheStreet) -- Groupon ( GRPN - Get Report) shares plunged on Monday as two members of its board, including Starbucks ( SBUX - Get Report) CEO Howard Schultz, resigned.

Schultz is stepping down immediately, while venture capital firm Accel Partners' Kevin Efrusy's resignation from the board of directors will be effective as of the company's annual meeting in June. Groupon stated in a press release that Daniel Henry, the chief financial officer of American Express ( AXP) had joined the board and Robert Bass, a vice chairman of Deloitte LLP should join its board after a shareholder vote at the annual meeting.

"With their deep financial, accounting and operational experience, Dan and Bob will provide invaluable expertise to the Board going forward," said Eric Lefkofsky, Groupon Chairman.

Groupon has been besmirched by accounting issues since its IPO, when it used a controversial method of accounting to inflate its revenue drastically. It recently restated fourth-quarter earnings, citing a shift in the company's fourth-quarter deal mix and higher price offers, which have higher refund rates.

Groupon could not immediately be reached for comment.

Shares traded down sharply on Monday, down 10.56% to finish at $10.71.

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-- Written by Chris Ciaccia in New York

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