Moreover, O'Malley's campaign spent about $500,000 more than it raised between July and September, a pace that it can't sustain without running out of money.
By contrast, Hillary Rodham Clinton reported raising $29.5 million during the latest quarter, finishing with $33 million in the bank. And Sen. Bernie Sanders (I-Vt.) raised $26.2 million, ending up with $27.1 million cash on hand.
O'Malley's take for the last three months is less than the roughly $2 million he raised during the previous quarter, which ended in July. He had been an official candidate for only about a month at that point.
The former governor had been counting on a breakthrough performance in this week's first Democratic debate to change his fate. But most analysts suggested that the debate in Las Vegas was unlikely to fundamentally alter the dynamics of the race.
In a statement, O'Malley's campaign said it had received a burst of contributions in recent days but didn't offer a figure.
"For the first time, Governor O'Malley was able to introduce himself and his record of progressive achievements to a national audience this week," said campaign manager Dave Hamrick. "This is a fight that is just getting started, and our campaign has raised the funds necessary to continue introducing Governor O'Malley, doing the retail work in early states like Iowa and New Hampshire, and building the grassroots support we need to win."