06/29/2012 12:12 pm ET Updated Jun 29, 2012

Mitt Romney Builds Fundraising List On Health Care Ruling, Obama Campaign Says It Raised More (UPDATE)

WASHINGTON -- In the 24 hours since the Supreme Court handed down a 5-4 decision upholding the majority of the landmark Affordable Care Act, including the mandate to obtain health insurance, Mitt Romney's campaign has raised an impressive $4.6 million from more than 47,000 donors. The fundraising drive marks the first real "money bomb" of Romney's campaign and will be a big boost to the presumptive Republican nominee's so-far-lackluster efforts to attract grassroots donors.

President Barack Obama's campaign did not send out a fundraising appeal after the decision, but told The Huffington Post via email Friday that it had nonetheless outraised the Romney campaign the previous day.

"It's perverse that Mitt Romney won't share details about what he'd do for the millions he'd leave uninsured or at the whims of insurance companies when he 'kills Obamacare dead,' but he'll share the hourly details of his fundraising after the Supreme Court ruling," wrote Obama campaign communications director Ben LaBolt. "We've outraised the Romney campaign in that time period but that's not the point -- our supporters are more committed than ever to ensuring that insurance companies can't drop coverage for people who get sick or discriminate against people with preexisting conditions by reelecting the President."

The Obama campaign had told HuffPost on Thursday that it would not be releasing fundraising numbers for the day and does not discuss precise numbers except in regards to its filings with the Federal Election Commission.

The Romney campaign's haul, even if it is less than that raised by the Obama campaign, represents an important milestone.

Prior to Thursday's money bomb, Romney had raised money from only 81,663 individual donors, one-third of the number giving money to Obama. Depending on the number of new donors among the 47,000-plus who gave after the Supreme Court's ruling, the Romney campaign may have just vastly expanded its donor list, an vital tool for a presidential run.

Patrick Ruffini, a Republican strategist and president of digital consulting firm Engage, explained that, prior to Thursday, it appeared as though Romney was going to run a "post-email digital campaign, with lots of emphasis on Facebook and targeted advertising, rather than doing things things to grow the size of the list -- which, at 13 million, was king for Obama."

"It now looks like conservatives can be energized to contribute directly to the Romney campaign, so corralling as many people on their email list so they can convert them to donors becomes a wise investment of time and resources for the campaign," Ruffini said. "If Romney can complement his strong offline fundraising advantage with a strong online component, that magnifies his financial advantage over Obama."

UPDATE: 5:03 p.m. -- According to officials with the Romney campaign, 65 percent of the donors that gave during the post-Supreme Court ruling money bomb were new donors. That's more than 30,000 new donors for the campaign.

Campaign cash will only be part of the equation this election season. Check out a list of the top super PAC donors below.

Donors Giving $500,000-Plus To Super PACs