May 21 (Bloomberg) -- Barack Obama raised $30.7 million last month, eclipsing both Democratic rival Hillary Clinton and presumptive Republican nominee John McCain.

Clinton raised $21.1 million and lent her campaign $5 million, Federal Election Commission records show. McCain took in $18 million, his biggest haul to date.

``There is no doubt that Obama is a formidable fundraiser, but his intake last month was smaller than previous monthly totals,'' said Costas Panagopoulos, director of Fordham University's Center for Electoral Politics and Democracy in the Bronx. ``This is at least one indication that the Obama money machine may be running, slowly, out of steam.''

That machine continues to be fueled by small donations. The Obama campaign reported 200,000 new donors last month, bringing its total to 1.5 million. Of April's donations, 94 percent were under $200, allowing the campaign to ask those contributors for more money later.

The Illinois senator has now raised $256 million for the primary election, just behind the $262 million taken in by President George W. Bush in 2004. Obama has already surpassed the $219 million raised by 2004 Democratic presidential nominee John Kerry.

Obama finished the month with $37.3 million to spend on the Democratic presidential nomination, spokesman Bill Burton said. He also had $9.2 million for the general election, Burton said.

Clinton had her second-biggest fundraising month of the year, with almost half of it, $10 million, coming in the 24 hours after she won the April 22 Pennsylvania primary. She had $29.7 million in the bank, though at least $23 million was collected for the general election and can only be spent if she wins the Democratic nomination.

She loaned her campaign $5 million last month and another $1.4 million in May, part of the $11.4 million in personal funds she has used for her presidential run. Clinton also reported $9.4 million in unpaid bills.

Campaign Chairman Terry McAuliffe said Clinton, a New York Senator, has offered to spend more of her own money.

``I have told her we may need it,'' he said. ``But we don't need it yet.''

Arizona Senator McCain had $21.8 million to spend at the end of the month. He has raised $93.2 million for his campaign.

To contact the reporter on this story: Jonathan D. Salant in Washington at jsalant@bloomberg.net;

Last Updated: May 21, 2008 01:02 EDT