Under current tax law, anybody investing an IRA in a private-equity fund, as Mr. Romney did, would likely incur a hefty special tax on “unrelated business income,” also known as UBIT. This tax, assessed at a maximum 35% rate, is meant to discourage tax-exempt entities such as an IRA, pension plan or endowment fund from unfairly competing with for-profit, taxpaying entities by operating a business without paying taxes on it. Investing in a partnership that uses debt to buy companies would trigger the tax, experts said.
It isn’t known whether Mr. Romney paid UBIT. His filings suggest use of a strategy involving offshore funds sometimes employed to avoid it, according to several experts.
One method used by tax lawyers is to have the IRA invest through an offshore affiliate of the private-equity firm, known as an offshore blocker corporation, which in turn invests the same money in the private-equity partnership. The tax is avoided because the IRA technically is investing in the offshore corporation, not in a private-equity partnership.
Tax experts say that might explain why Mr. Romney’s IRA includes holdings in Bain entities based in offshore locations, including one Cayman Islands entity that Mr. Romney listed as having a value between $5 million and $25 million.