"Sure, he would be helpful, but I don't think John McCain will ask him to be vice president for that," said Mel Sembler, a former ambassador to Italy and a former member of Romney's finance team.

The former Massachusetts governor has made it clear he plans to raise money for Republicans regardless of whether McCain picks him as his vice presidential nominee. Romney is now spending most of his time traveling around the country headlining fund-raisers for Republican candidates. And he has not raised any money to repay the $44.6 million he loaned his campaign and has no plans to do so, said Eric Fehrnstrom, a spokesman for Romney's new political action committee, Free and Strong America.

Romney's personal fortune, built during his years as a corporate executive with Bain & Co. and Bain Capital, was estimated to be as much as $250 million last summer.

Few other potential GOP vice presidential picks would be as wealthy as Romney. The exceptions would be Michael Bloomberg, mayor of New York, and Meg Whitman, former chief executive of eBay and a leading Romney fund-raiser who is now a McCain campaign cochairwoman. But a vice presidential candidate's wealth would only matter if the ticket opted out of the public financing system, which prohibits candidates from accepting private donations.

Since the post-Watergate reforms of the 1970s, presidential candidates of both parties have relied on public money to finance their general election campaigns. But as he closes in on the Democratic nomination, Barack Obama, who once promised to use public financing, has sent signals he might change his mind in order to take full advantage of the vast online network that has helped him break all presidential fund-raising records. McCain's campaign would not say whether he would follow Obama's suit if the Democrat opted out.

At the end of April, Obama had brought in more than $265 million, compared to nearly $97 million for McCain. Hillary Clinton had raised about $215 million.

In any case, many Romney supporters said his personal wealth is not nearly as important as his fund-raising capacity. In the primary race, Romney proved his ability to reach beyond the usual GOP donor circles, tapping connections in Michigan, where he was born and his father was a beloved governor; in the business world, through his connections at Bain and Harvard Business School; in Utah, where he led the 2002 Winter Olympic Games; and in the Mormon community, where the Romney family's roots go back generations.

"We brought in a lot of new blood, people who hadn't done it before, and who got motivated," Tellefsen said. "That was the secret to our success."