It's no secret that GOP presidential candidate Mitt Romney is a very wealthy man, thanks to his years at Bain Capital, a private equity firm he founded and ran until 1999. But two recent news investigations found that the former Massachusetts governor holds a number of offshore assets that election laws don't require him to disclose, suggesting that he could have a lot more money than voters think. Here's what you should know:

How rich is Romney?

Estimates from his campaign have put his personal wealth around $250 million, although Romney has declined to provide a precise figure. But recent reports by Vanity Fair and The Associated Press suggest that Romney and his wife, Ann, might have considerable offhsore assets that the public doesn't even know about.

How much are these offshore assets worth?

A lot, potentially. Bain "has at least 138 funds organized in the Cayman Islands," says Nicholas Shaxson at Vanity Fair, "and Romney himself has personal interests in at least 12, worth as much as $30 million, hidden behind controversial confidentiality disclaimers." One holding, according to the AP, recently posted earnings of $1.9 million. Another, the Bermuda-based Sankaty High Yield Asset Investors Ltd., is much more of a mystery. It's one of several hedge funds Bain Capital has used as a vehicle in multimillion-dollar investment deals, such as the $1 billion takeover of Domino's Pizza. Romney's stake in Sankaty was transferred to Ann's name the day before Mitt was sworn in as Massachusetts governor in 2003, but "even after examining [the Romneys' 2010 tax] return, we have no idea what is in this company," says Shaxson. Still, we suspect that "it could be valuable, meaning that it is possible Romney's wealth is even greater than previous estimates."

Why hasn't Romney disclosed these offshore assets?

He doesn't have to. By law, assets held in such offshore funds and companies don't have to be listed in state and federal ethics filings.

Should this have any bearing on the presidential race?

Predictably, Democrats and Republicans disagree on that question. The Obama campaign says Romney's undisclosed overseas holdings and tax havens smell fishy. "We need to choose someone who invests in America, not in a Swiss bank account," Vice President Joe Biden tweeted. The Romney campaign says their man has done everything by the book, disclosing all assets and paying all taxes that the law requires.

What will voters think?

There's a partisan divide over that one, too. This new round of digging into Romney's finances, says Dan Riehl at Riehl World View, only proves once again that Obama's liberal media lapdogs are out to get Mitt. Hold on — "Romney has made business experience the central pitch of his candidacy," says Ben Adler at The Nation, "so how can he claim that how he manages his money is irrelevant?" Well, like Romney's frequently vague policy positions, his "opaque finances" are a mixed bag, says Alexander Burns at Politico. But clearly, Romney is willing to take "a certain amount of heat over his lack of detail and transparency, in order to deny his critics and political opponents information they might use to attack him."

Sources: Associated Press, The Nation, New York Daily News, Politico, Riehl World View, Vanity Fair

Read more political coverage at The Week's 2012 Election Center.