The Chicago Sun-Times reported that Evercore business analyst Ken Sena, in a note to investors, said payment from merchants who offer deals through what the company calls Groupons had dropped to "just $32 million for the first six months of 2012."
In the same period of 2011, that figure was $217 million, the newspaper said.
On Friday, Groupon shares closed at $4.75, its lowest ever, as the Chicago firm has lost 76 percent of its value since its initial pubic offering, which priced shares at $20.
"Should billings declines persist, we see a potential for cash burn as Groupon would find itself in a situation where it would be paying cash to merchants on a larger (prior) business scale relative to the cash it would be collecting," Sena wrote in the business report.
Total revenue at Groupon rose 45 percent in the second quarter from the second quarter of 2011, but came in short of expectations at $568.3 million, compared to the forecast of $573 million.
A Groupon spokesman said Friday the company has $1.2 billion in available cash, a portion of its balance sheet that has grown for eight consecutive quarters.
Sena dropped his outlook on Groupon stock from $6.50 to $3, but Chief Executive Officer Andrew Mason said the company's strategy was sound.
"As long as we focus on execution and making our customers happy, over time, we will deliver the results," he said.