Groupon has been struggling lately with its stock, so the company decided to replace its CEO. (0Roberto0, Creative Commons)

Groupon decided to oust Mason one day after its first-quarter revenue was reported between $560 million and $610 million, falling well short of the $647 million that analysts projected. Additionally, a miserable fourth-quarter report didn't help in which resulted in Groupon's stock falling more than 20 percent. Reports had already surfaced before then that Groupon was thinking about replacing him as CEO. 

Co-founder Eric Lefkofsky and Vice Chairman Ted Leonsis will serve as interim co-CEOs until Groupon chooses finds its replacement. Mason was Groupon's founder, and he was the CEO for the previous four and a half years. He sent a letter to his employees after finding out that he would be replaced.

Groupon's shares actually rose 13 percent after Mason's departure was announced to its shareholders. 

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