Mitt Romney outraised President Obama in 19 states in May, including four of nine critical swing states, records released Wednesday night show. But as the former Massachusetts governor solidified his position in the party and teamed up with the Republican National Committee, which can legally accept much larger checks than a candidate, his reliance on a few wealthy donors at the expense of a large base also grew.
Mr. Romney and the RNC raised $58 million in May, virtually even with the $59 million raised by Mr. Obama and the Democratic National Committee. But nearly half of Mr. Romney’s haul — $27 million — came from donors giving $10,000 or more and $18 million came from those giving $30,000.
On the Obama side, $6.8 million came from $30,000-plus donors and $11.5 million came from $10,000-plus givers.
The overall dollars are a victory for Mr. Romney, allowing him to assemble a ground game, but the small slice of the population from which they come are a continuing handicap for a presumptive nominee who needs to demonstrate that he can win over wide swaths of the base. Many of the donors who gave to the party committee after it joined ranks with Romney already had given the maximum to the campaign, so they don’t represent new donors.
Mr. Romney’s campaign received 18,000 donations of $200 to $5,000 in May, up from 9,000 in April. Despite knocking out several challengers, that donor base is only double what it was in January, when the race had hardly begun.
Mr. Obama received 18,000 such donations in April and 29,000 in May. (The figures do not include the smallest donations since those are not reported individually.)
In May, Mr. Romney increased his staff from about 90 to 150, still far short of the 700 who work for Mr. Obama’s campaign. But the Republican also has spent at a slower rate, potentially saving for a late blast.
The largest financing bloc of Mr. Romney’s bid so far has been the company he used to run, Bain Capital, whose employees have given $330,000. That’s followed by Goldman Sachs ($215,000), Morgan Stanley ($210,000) and Credit Suisse ($170,000).
Four members of the Romney family, including the candidate and his wife, also gave the maximum $30,800 each to the RNC last month.
While Mr. Romney relied heavily on the RNC maximum givers, the biggest money to both parties came in the form of donations to super PACs, including Priorities USA, a fund blessed by Mr. Obama that raised significant amounts for the first time, bringing in $4 million despite professed disgust by liberals at the concept of unlimited-money super PACs.
On the Republican side, American Crossroads, the group of former George W. Bush adviser Karl Rove, emerged as the dominant quasi-party committee, raising $4.5 million last month — 10 times what a similar group, FreedomWorks, did. FreedomWorks is a corporate-backed group with a tea party tinge, and it opposed Mr. Romney as the GOP nominee before reluctantly embracing him.
Among the donors who gave $1 million or more to political groups in May:
• Joe Craft, chairman of Alliance Holdings Group in Tulsa, Okla., along with his company, gave $1.7 million to American Crossroads.
• Crow Holdings of Dallas gave $1 million to American Crossroads. Former hotel executive James Carreker, of the same address, is a Romney donor.
• Houston trial lawyer Steve Mostyn, who represents people against insurance companies, gave $1 million to Priorities USA.
• Retiree Barbara Stiefel of Coral Gables, Fla., did the same.
• Former PayPal executive Peter Thiel, who formerly gave to a Ron Paul super PAC, gave $1 million to the Club for Growth, a super PAC that pushes congressional Republicans to the right by mounting challengers in primary elections.