Last night, Groupon just released its earnings for the quarter ending 30th September 2015. Revenue was below expectations, and flat compared with the same period last year. The company issued revenue guidance for Q4 of $815-865m, which would be a drop on the same period last year ($883m), suggesting that growth has stalled. The share price dropped by 25% in after-market trading.

There’s more bad news buried in the balance sheet numbers. Groupon benefits from a negative working capital model, where it receives gross revenue 60 days before it has to pay its suppliers. During the year before its IPO, Groupon’s current liabilities exceeded its current assets by hundreds of millions of dollars, which meant that it was reliant on continued growth to remain solvent.

The money it raised from the IPO eliminated that deficit but the situation deteriorated sharply during the past quarter – net current assets (i.e. current assets less current liabilities) plunged from over $300m to just $87,000.

Part of the decline is attributable to a share repurchase program – the company spent $192.9m repurchasing shares (which seems ill-advised with hindsight, given that it paid an average of $4.36 for shares that are currently trading at $3.09).

If revenue growth has indeed stalled, and the decline in net current assets continues into negative territory, Groupon could once again find itself at risk of the loss-of-confidence scenario I described four years ago:

..the question that merchants should be asking themselves is this: Will Groupon be able to pay me what they owe me in 60 days time?

If a merchant ever thinks that the answer to that question might be “No.”, they’ll opt not to offer deals through Groupon. Why would you sell (at a heavy discount, mind you) your products or services through a company that may not be able to pay you? Better to take the guaranteed revenue from normal customers who pay up front, than risk selling through Groupon and never recouping a penny.

Without deals to offer to the people on its mailing list, Groupon can’t make sales. If it can’t make sales, it can’t generate revenue. And, if it can’t generate revenue, its negative working capital model will very rapidly lead it to run out of cash.

The most dangerous thing about this situation is that it doesn’t matter whether or not Groupon actually can pay the merchants. If enough merchants believe that Groupon is not creditworthy, a tipping-point will be reached and it will become a self-fulfilling prophecy.

So, Groupon’s negative working capital model exposes it to the risk that a loss of confidence could cause it to become insolvent.

When I wrote that, I questioned the wisdom of Groupon’s decision to pay out most of the money it raised in its Series C, D and E rounds to previous investors. Today, I wonder why it’s depleting its cash to repurchase shares when there’s a real risk that it might need that cash to remain solvent.