"I think most companies would kill for those kinds of growth rates. We're quite proud of them," Mason said in an interview, referring to 45 percent growth year over year.
Mason said looking at data from quarter to quarter was "simply the wrong way to evaluate an e-commerce company."
Investors have criticized the company for declining revenue growth between quarters, The Chicago Tribune reported Saturday.
"We're an e-commerce company that does over $5 billion in sales every year, and like every other e-commerce company that's operating at this scale, you have to look at us at a year-over-year basis," Mason said.
By comparison, "Amazon has something like two quarters a year of negative quarterly sequential growth," he said.
He also said the company had ambitions growth plans.
"Any time you see us launch a new channel like Groupon Goods or Groupon Now or Groupon Getaways, those are the sorts of investments we're doing in order to expand our relationship with customers and increase wallet share," he said. "These types of things are investments. If we were purely interested in optimizing for immediate term revenue, we might make different decisions."