THE crackdown by the US on so-called corporate inversions should, in theory, make the tax avoidance strategy more difficult to do for companies in the future.
But there are questions around whether the moves by the US Treasury this week will affect companies that are already in the process of closing or negotiating an inversion deal.
In an inversion, a US corporation avoids US taxes by buying or setting up a foreign company in a country, such as Ireland, and then moving its tax domicile to that country.
President Obama, who has been a critic of the strategy, said the Treasury Department's steps would "discourage companies from taking advantage of corporate inversions".
Peter Vale, tax partner with Grant Thornton, agrees. But he believes it will ultimately have little impact on Ireland.
"It may impact on deals that haven't yet completed, but from Ireland's perspective it shouldn't make any difference," he told the Irish Independent.
"When you invert, you're not bringing a pile of jobs into Ireland. We don't want to be out there to be seen to attract inversions, it doesn't do anything for us, it doesn't mean we're bringing any more jobs in."
Inversions have surged in the past year, pursued by big companies. The move has raised questions about several deals in negotiation including the one involving medical technology group Medtronic, which is working to close a deal with rival Covidien and move its executive base to Ireland.
The move has also raised questions about the planned merger between Chiquita and Fyffes, which, if it gets the go-ahead from the European Commission, would result in the world's largest banana company. The US government action eliminates certain techniques inverted companies currently use to gain tax-free access to the deferred earnings of a foreign subsidiary, significantly diminishing, in theory, the ability of inverted companies to escape US taxes.
It also makes it more difficult for US entities to invert by strengthening the requirement that the former owners of the US company own less than 80pc of the new combined entity.
Companies that do inversions, which are legal and already subject to certain restrictions, say they are only trying to minimise their tax bills, which investors expect.
Padraig Cronin, head of tax and legal services at Deloitte Ireland, said the move could bring forward the likelihood of wider tax reform in the US.
"It's interesting that when something reaches a particular profile in the US in respect of what they regard as unacceptable, they are able to move," he added.
"It would equally be in their power to do something about the so-called 'Double Irish', and they have chosen not to do that."
The move has already spooked investors.
On Tuesday almost €10bn was wiped off the value of shares of about a dozen companies on both side of the Atlantic.
Mr Vale said the rules will impact to "some degree" as it may dissuade companies from considering the move in the future.
"They've been talking about inversions for a number of years in the US. This does seem to be different in the sense that this is an indication that something will actually happen, as supposed to just talk," he said.
"Yes it will probably have an impact on some inversions. But will it adversely impact on Ireland, no I don't think so at all."