President Obama has amassed a formidable team of more than 240 big-dollar fundraisers just three months into his 2012 reelection campaign, including more than two dozen bundlers who have each raised at least $500,000.

The bundler list and other campaign data released Friday provide further evidence of an astonishing fundraising effort by Obama amid a struggling economy and mediocre presidential approval ratings.

Obama’s official campaign raised $46.3 million and spent $11 million from April to June of this year, according to new documents filed with the Federal Election Commission. That left it with a whopping $37 million in the bank, including money left over from the first quarter. Obama also brought in $39.3 million in a joint fundraising effort with the Democratic National Committee, the filings show.

The numbers put Obama far ahead of his GOP rivals, who are led by Mitt Romney with nearly $18.4 million raised. The former Massachusetts governor also reported $12 million of cash on hand at the end of June.

The rest of the field lags well behind, and some, including former House speaker Newt Ging­rich, are already in the red.

Former Minnesota governor Tim Pawlenty spent $2 million in the quarter, leaving him only $1.4 million in primary cash to battle Romney and other contenders in the weeks ahead. Rep. Michele Bachmann (R-Minn.), on the other hand, has $3.6 million in the bank only weeks after declaring her candidacy.

For Obama, the sheer number of bundlers — and the volume of donations they represent — signals another potential juggernaut like 2008, when he shattered all records by raising $745 million. During his first campaign, he had 47 bundlers who raised $500,000 or more — a total he is already more than halfway to matching.

Obama’s biggest bundlers include longtime supporters such as Hollywood mogul Jeffrey Katzenberg, former New Jersey governor and senator Jon Corzine, and fashion editor Anna Wintour. But there are new names on the campaign’s bundlers list as well, such as Marc Benioff, a tech CEO who runs

Several of the key bundlers, including Benioff, held events at their homes in which Obama came. These events usually gave donors special access to Obama, including the chance to ask the president direct questions in a closed-door atmosphere.

Hollywood super-agent Ari Emanuel, the brother of former White House chief of staff Rahm Emanuel, helped raise between $50,000 and $100,000.

Romney did not release a full list of bundlers, but his campaign was required to disclose bundling by six registered lobbyists, totaling $517,000 in contributions. The lobbyists included Patrick Durkin of Barclays, who raised $168,000, and Wayne Berman, with Ogilvy Government Relations, who raised $102,000.

The lobbyist bundler requirement was put in place by an ethics law sponsored by then-senator Obama, who has not accepted contributions from registered lobbyists or corporate PACs in his presidential bids. The Obama campaign attacked the GOP field on Friday for declining to identify their top fundraisers.

“President [George W.] Bush disclosed his bundlers, but the current GOP field has not followed suit, raising questions about the extent to which special interests are funding their campaigns,” said spokesman Ben LaBolt.

Romney spokeswoman Andrea Saul responded, “All of our donors are public.”

The Obama campaign has sought to emphasize the grass-roots side of his fundraising operation, noting that donors who gave $200 or less accounted for about a third of his total. The campaign says it had 550,000 donors in the second quarter, with an average contribution of less than $70.

But the data show that wealthier contributors are also a crucial part of his fundraising operation. Obama raised nearly a quarter of his total contributions, more than $20 million, from people who gave the maximum possible donation of $5,000 to his campaign and $30,800 to the Democratic National Committee.

The share of Obama’s funding from small donors lags his entire 2008 campaign but is well ahead of the first quarter of 2007, when Obama’s bid was getting off the ground and had yet to generate the groundswell of enthusiasm that eventually led 4 million people to donate money to him.

The numbers are more bleak for many Republican candidates. Pawlenty, who has strugggled to gain traction in the polls, raised less than $4.5 million and spent nearly $2.5 million, records show.

Gingrich, whose presidential bid imploded earlier this summer amid mass resignations and financial problems, reported $1 million in debt — about half of which is owed to Moby Dick Airways, a charter jet service.

Herman Cain and Rick Santorum each had less than $500,000 in the bank at the end of June.

The report was brighter for Bachmann, whose poll numbers have soared in recent weeks. Her campaign says she has pulled together $4.2 million for her newly minted presidential committee, most of which she had on hand at the end of June. At least $1.6 million came through contributions of $200 or less.

Romney was the most reliant of the Republican field on big donors, with 70 percent of his money coming from people who gave the $2,500 maximum allowed for a primary. So he won’t be able to go back to them for money in the primary campaign. (Obama, by contrast, can still tap big donors for both the primary and general elections.)

Only 6 percent of Romney’s contributions came in increments of $200 or less, compared with 11 percent for Pawlenty and higher proportions for others.

Staff writer Perry Bacon Jr. contributed to this report.