Richard Lardner? and Stephen Braun

WASHINGTON: A few weeks before the Republican primary in Florida in January, the billionaire owner of the NFL’s Miami Dolphins hosted a fundraiser for Mitt Romney at his oceanfront home in Palm Beach. The average voter wouldn’t know about the event at the home of Stephen Ross because Romney’s campaign doesn’t follow the practice of other major presidential candidates who have willingly identified big-money fundraisers and the amounts they collect.

A review by the Associated Press of campaign records and other documents reveals hints about the vast national network of business leaders bringing in millions to elect Romney. The same month that Ross invited friends and colleagues to his home, for example, Romney’s campaign received $317,000 from nearly 150 people who share Ross’ exclusive ZIP code on Florida’s east coast, according to Federal Election Commission records. That mysterious surge of donations outpaced all contributions to Romney during the previous year from the wealthy Palm Beach area, when the campaign collected $270,000 over nine months. Romney got $21,000 more from residents there in February.

Unlike President Barack Obama, Romney’s campaign will not identify his major fundraisers, and federal law doesn’t require him to. The AP identified several of Romney’s “bundlers” through interviews, finance records, event invitations and other publicity about campaign events. The lack of transparency by the Romney campaign prevents voters from knowing who wields influence inside the GOP frontrunner’s campaign and how their interests might benefit if he is elected. Romney is in California this week for at least five private fundraisers.

Bundlers are typically well-connected business and banking executives who tap their professional and social networks to steer individual contributions from others to the campaign in amounts that can range from $10,000 to well over $500,000. Experienced bundlers can reach these highest amounts quickly. Persuading 25 couples to attend a VIP reception with the candidate for $2,500 each — the maximum an individual can give a campaign — raises $125,000 in a single evening.

Even in the era of “super” political action committees, which can pull in millions of dollars in unlimited and effectively anonymous contributions to support candidates, bundlers are their own campaign forces. Unlike super PACs, which can’t legally coordinate with candidates, bundlers raise large amounts deposited directly into a campaign’s bank account — money that can be spent to pay for salaries, get-out-the-vote efforts and advertising.

This presidential election is expected to be among the costliest ever. Obama’s re-election campaign has raised just over $151 million. His campaign released the names of its bundlers in late January, and the list illustrates how important these elite fundraisers have become. More than 440 bundlers collected at least $75 million to help Obama win a second term, including 61 people who each raised at least half-million dollars.

Fundraising has been a bright spot for Romney during the bruising GOP primary. Romney has built a potent organization that has pulled in nearly $75 million. Two-thirds of the total — nearly $49 million — came from people who gave the $2,500 maximum, which can be indicative of contributions pulled together by bundlers. Just $6.5 million, or 9 percent, came from supporters who gave $200 or less. The emphasis on top-tier donations indicates an active network of fundraisers who are targeting high-end contributors.

“Romney is less focused on small donors than any other candidate at this stage of the campaign in recent memory,” said Michael Malbin, director of the nonpartisan Campaign Finance Institute. “And that is parallel to a larger problem: He has not yet excited the passions of the kind of people who give small contributions or volunteer their time.”

One prominent Romney supporter, Lewis M. Eisenberg, said that even with the rise of super PACs like Restore Our Future, which helped Romney pay for important advertising, the campaign is still dependent as ever on “hard money” that pays for salaries, state organizing, television ads, direct mailings and other expenses.