Republican donors are beginning an exodus away from presidential nominee Mitt Romney, Fox Business' Charlie Gasparino reported Monday, a disturbing sign for the Republican nominee just five weeks before the election.

The group of wealthy donors see giving more funds to the presidential candidate as politically fruitless as Romney continues to trail President Obama in polls, and might prefer to allocate their resources to House and Senate candidates.

Gasparino writes that it "could be the beginning of a mass exodus of big money donors diverting their cash away from the Republican presidential hopeful and toward Republican candidates for the House and Senate races more likely to win in November."

The Romney campaign disputed the report in an email, calling it "not true."

"Many supporters like to also donate to other candidates in addition to the support they have already given Gov. Romney," Romney campaign spokeswoman Amanda Henneberg told Business Insider.

The report follows a week-plus of bad polling for the Romney campaign, combined with an increasingly narrow and difficult electoral path. At the same time, Republicans still have a decent chance to win the Senate this year, provided they have enough resources in a few crucial states.

While the House is far from vulnerable for Republicans, maintaining a strong majority allows for a stronger caucus and leeway for possible defections. And a stronger position — or an outright majority— in the Senate could hamstring a potential second Obama term.

Moreover, smaller races tend to be cheaper and easier to sway.

The average cost of winning a seat in the House in 2008 was $1.1 million, and the average cost of a Senate win was $5.6 million. As it stands, the two presidential candidates have spent more than $700 million combined so far trying to win the presidency.

One thing that could turn around the emerging trend would be a slam dunk in the debate on Romney's part, according to Gasparino.

“The debates will be very important,” one source told Gasparino. “If Romney does well that money could come back.”