Now that Mitt Romney has clinched the GOP presidential nomination, he has started chipping away at President Obama's campaign fundraising lead. Romney still has less money in the bank, but he and his party raised nearly as much as Team Obama in April. Pro-Romney super PACs did even better, out-raising the pro-Obama super PAC Priorities USA Action. Is Obama's spending advantage evaporating? Here, a brief guide:

How much money do Obama and Romney have?

Obama's re-election effort wrapped up last month with $147 million on hand. Romney and the Republican National Committee had just $61.4 million. But Obama gained that lead while Romney shared GOP donors with his rivals in a bitter primary battle. Now Romney has the donors all to himself, and he has started a joint fundraising effort with the Republican National Committee, so he's managing to pick up steam as Obama's fundraising shows signs of slowing.

Will Romney catch up?

It's very possible. Last month, Romney and the RNC collected $40.1 million, almost as much as the Obama camp, which along with the Democratic National Committee raised $43.6 million. Of the collected Republican donations, $11 million went directly to Romney's campaign, while $25.7 million of Democratic donations went to Obama. That shows how important locking up the nomination was for Romney. Donors can write bigger checks to state party committees, and April was the first month when those groups started pitching in for their new presumptive nominee — and party fundraising is just one piece of the money race.

What are the other factors?

This time around, super PACs are tipping the scales against Obama. The pro-Obama super PAC Priorities USA Action raised $1.6 million in April, about $3 million less than the pro-Romney super PAC Restore Our Future. And other Republican-aligned super PACs, including those that backed former Romney rivals Newt Gingrich and Rick Santorum, also could come into play in the general election campaign. American Crossroads, the GOP super PAC founded in part by Karl Rove, has spent $27 million on ads this year, many of them hammering Obama, and the group announced last week that it would spend another $25 million on a month-long ad campaign in 10 states.

So Romney will definitely have the edge?

In one sense, Romney's already in the lead. "With super PACs in [the] mix?" Obama strategist David Axelrod said via Twitter. "Slam dunk Team Romney will outspend us." Romney and the groups backing him have outraised Obama and his supporters $402 million to $340 million, according to Politico's analysis of federal records and voluntary disclosures. In 2008, before super PACs existed, Obama outspent Sen. John McCain by more than two to one. That won't happen to Romney, says Kenneth P. Vogel at Politico, "and the former Massachusetts governor might even end up with a financial advantage over the president."

Sources: Hot Air, Los Angeles Times, New York Times, Politico