There may be nothing better for a lawyer's book of business than uncertainty in the law, so while new regulations announced Monday that aim to limit the controversial corporate inversion may put a stop to some of those deals, it won't stop the need for tax attorneys to dissect these new rules and the promise of continued political machinations.

Corporate inversions, a mechanism increasingly used by U.S. companies over the past decade to reincorporate in a foreign jurisdiction to reduce their tax burden, have come under fire from the Obama administration and others as "unpatriotic." These deals are typically done through a merger with a foreign company that results in the U.S. company maintaining much of its operations in the United States but much of its ownership and tax liabilities overseas.

The U.S. Department of the Treasury issued a notice Monday, effective immediately, that new regulations would be forthcoming aimed at increasing the legal requirements for corporate inversions.

The tax lawyers who spoke to The Legal said these new regulations will force parties that have announced deals that haven't closed yet to reexamine whether it still makes sense to move forward. There is also a question, the attorneys said, of whether there is any legislation that authorized the Treasury Department to issue such regulations, making litigation likely. Ultimately, the attorneys said, the issue can only be fully addressed by tax reform from Congress, which the attorneys said seems unlikely.

All of that leaves clients with a lot of questions moving forward.

"The rules in existence even before yesterday had hurdles in them," said Duane Morris international tax partner Hope P. Krebs on Tuesday. "This wasn't some huge loophole that was really easy to do and didn't require a lot of analysis, review, business operational concerns, legal concerns. … What happened yesterday is going to cause people to retrench and figure out whether it still makes good sense" to undergo a corporate inversion.

Krebs said it seems as if there hasn't been a day that has gone by in the past three to six months that she hasn't gotten a call from clients about whether a corporate inversion would make sense for them. But there are many more inquiries than there are deals completed, she said. …

In the short term, Krebs said, fewer deals will be announced and those that have already been announced will take time to review before rushing to close. While the rules are contained in a few sections of the Tax Code, it may affect other areas and will require a detailed legal analysis, she said. …

Krebs said Congress thought it fixed the growing inversion trend with the American Jobs Creation Act of 2004, but that didn't stop companies from inverting then. She said she didn't think they would stop now, because at the end of the day companies find they are still better off paying a lower worldwide tax rate as an inverted company.

As Krebs noted, every time new tax regulations are implemented, there is a proverbial room full of tax lawyers looking at how to find a way around them.

"It's just the nature of the beast," she said.

Reprinted with permission from The Legal Intelligencer, © ALM Media Properties LLC. All rights reserved.