As part of the bailout of the auto industry in 2009, Obama's Treasury Department authorized spending $1.7 billion of government funds to get a bankrupt Michigan parts-maker back on its feet — as a British company. While executives continue to run Delphi Automotive from a Detroit suburb, the paper headquarters in England potentially reduces the company's tax bill by as much as $110 million a year.

The Obama administration's role in aiding Delphi's escape from the tax system may complicate the president's new campaign against corporate expatriation. After a wave of companies announced plans to shift addresses this year, Obama last month labeled the firms "corporate deserters."

The Delphi case also highlights how little attention the administration paid to the tax avoidance technique until recently. Only this year did Obama include a measure in his annual budget proposal to prevent some tax-driven address changes, which are known as "inversions." Thanks to gaps in a Congressional ban on contracts with inverted companies, his administration continues to award more than $1 billion annually in government business to more than a dozen corporate expats.