Mitt Romney's got some 'splaining to do. Big time. Vanity Fair has a nice, long article out today on Mittens' offshore investments, and what we all should know but don't because he hasn't honored us with full disclosure.

The article reads like a vacation brochure for very, very wealthy dudes:

Bermuda:

“To give but one example, there is a Bermuda-based entity called Sankaty High Yield Asset Investors Ltd., which has been described in securities filings as ‘a Bermuda corporation wholly owned by W. Mitt Romney.’… Romney failed to list this entity on several financial disclosures, even though such a closely held entity would not qualify as an “excepted investment fund” that would not need to be on his disclosure forms. He finally included it on his 2010 tax return. Even after examining that return, we have no idea what is in this company, but it could be valuable, meaning that it is possible Romney’s wealth is even greater than previous estimates. While the Romneys’ spokespeople insist that the couple has paid all the taxes required by law, investments in tax havens such as Bermuda raise many questions, because they are in ‘jurisdictions where there is virtually no tax and virtually no compliance,’ as one Miami-based offshore lawyer put it.”

Cayman Islands:

Because of his retirement deal with Bain Capital, his finances are still deeply entangled with the private-equity firm that he founded and spun off from Bain and Co. in 1984. Though he left the firm in 1999, Romney has continued to receive large payments from it—in early June he revealed more than $2 million in new Bain income. The firm today has at least 138 funds organized in the Cayman Islands, and Romney himself has personal interests in at least 12, worth as much as $30 million, hidden behind controversial confidentiality disclaimers. Again, the Romney campaign insists he saves no tax by using them, but there is no way to check this.

Switzerland:

These, plus the mandatory financial disclosures filed with the Office of Government Ethics and released last August, raise many questions. A full 55 pages in his 2010 return are devoted to reporting his transactions with foreign entities… The media soon noticed Romney’s familiarity with foreign tax havens. A $3 million Swiss bank account appeared in the 2010 returns, then winked out of existence in 2011 after the trustee closed it.

Canary Islands, El Salvador, Panama, Shadowy Rich Guys

Private equity is one channel for this secrecy-shrouded foreign money to enter the United States, and a filing for Mitt Romney’s first $37 million Bain Capital Fund, of 1984, provides a rare window into this. One foreign investor, of $2 million, was the newspaper tycoon, tax evader, and fraudster Robert Maxwell, who fell from his yacht, and drowned, off of the Canary Islands in 1991 in strange circumstances, after looting his company’s pension fund. The Bain filing also names Eduardo Poma, a member of one of the ‘14 families’ oligarchy that has controlled most of El Salvador’s wealth for decades; oddly, Poma is listed as sharing a Miami address with two anonymous companies that invested $1.5 million between them. The filings also show a Geneva-based trustee overseeing a trust that invested $2.5 million, a Bahamas corporation that put in $3 million, and three corporations in the tax haven of Panama, historically a favored destination for Latin-American dirty money—‘one of the filthiest money-laundering sinks in the world,’ as a U.S. Customs official once put it. Bain Capital has said it did everything required by the U.S. government to check that the investors were not associated with unsavory interests. U.S. law doesn’t require Bain to enforce the tax laws of its investors’ home countries, but the presence of Swiss trustees, Bahamas trusts, and Panama corporations would raise red flags with any tax authority.

Go read it and then ask yourself why he's not releasing more tax returns. I think you'll find the answer in that article.