This from the NYT:

Despite what appears to be a plump bank account and an in-house production studio that cranks out multiple commercials a day, Mr. Romney’s campaign has been tightfisted with its advertising budget, leaving him at a disadvantage in several crucial states as President Obama blankets them with ads.

One major reason appears to be that Mr. Romney’s campaign finances have been significantly less robust than recent headlines would suggest. Much of the more than $300 million the campaign reported raising this summer is earmarked for the Republican National Committee, state Republican organizations and Congressional races, limiting the money Mr. Romney’s own campaign has to spend.

With polls showing President Obama widening his lead in some of these states and the race a dead heat in others, Mr. Romney’s lack of a full-throttle media campaign is risky, especially as he struggles to get his message out over the din of news about his campaign’s recent setbacks.

In some states the disparity is striking. Mr. Obama and his allies are handily outspending Mr. Romney and the conservative “super PACs” working on his behalf in Colorado, Ohio and New Hampshire.

And in states like Florida, Iowa, Nevada and Virginia, where the Romney and Obama forces are roughly matching their spending dollar for dollar, the super PACs are responsible for nearly half the advertising that is benefiting the Republican nominee.