WASHINGTON – President Obama holds a cash advantage of more than 2-to-1 over Republican challenger Mitt Romney but the president's money advantage is beginning to dwindle.

Obama's campaign reported $115.1 million in the bank through April and the Democratic National Committee had about $24.2 million in its account at the end of last month.

Romney began raising money last month with the Republican National Committee and hauled in a combined $40 million, nearly on parity with Obama and Democrats, who raised about $43 million.

Romney and Republicans reported $61.4 million in the bank in April, meaning that in only a month, Obama's 10-to-1 cash advantage has fallen to 2-to-1 as Republicans prepare for the general election.

Although it has yet to appear in a finance report, Romney and his wife, Ann, donated in May the maximum $75,000 each to the Victory Fund, his campaign's joint fund with the Republican National Committee. It was their first donation this cycle to his campaign effort. A Republican familiar with the donation confirmed the amount but requested anonymity to discuss the matter ahead of the formal filing report.

Republicans are expected to be helped by GOP-leaning outside groups planning to raise hundreds of millions of dollars to defeat Obama. Obama campaign manager Jim Messina in a video to supporters earlier this week that the president has faced $57 million in negative ads.

"One of the most important things we can do is get our arms the fact that his election is going to be close given the historic challenges the nation faced when the president first came into office," Messina said.

The infusion of campaign cash is funding spring television ads attempting to shape the narrative of the presidential campaign. Obama is spending about $25 million on TV ads in May, an amount that was quickly matched by the GOP-leaning super PAC Crossroads GPS, which is advertising against Obama in 10 states.

Romney released an ad this week outlining plans for his first day in office, if elected, spending about $1.3 million to air the ad in Iowa, North Carolina, Virginia and Ohio.

A Democratic super PAC called Priorities USA Action is spending about $4 million on ads in five states attacking Romney's business background.