The U.S. Treasury's move to curb deals that allow U.S. companies to escape high taxes at home wiped a combined $12.3 billion off the shares of nearly a dozen companies on both sides of the Atlantic on Tuesday, as investors reacted to the surprisingly far-reaching action. But it was unclear whether the tougher stance adopted by the Obama administration on "inversion" deals that allow companies to escape high U.S. taxes by reincorporating abroad, which followed a wave of public criticism, would end any of the handful of deals currently in the works.