The U.S. Treasury department’s announcement on Monday of new rules to discourage U.S. companies from resorting to “inversion deals” to relocate to lower-tax countries has shaken the corporate world by its unprecedented force and reach. The proposed 0 billion merger between Pfizer and Allergan took a direct hit, and the two companies have called off the deal. Essentially, the rules sought to curtail tax inversions by addressing two controversial themes: One is the rise of the “serial acquirer,” a phenomenon where foreign companies grow too big through M&A deals, ostensibly to make inversion deals with a U.S. company compliant with U.S. law. Two, the rules target a practice called “earnings stripping,” where U.S. companies borrow money from their overseas subsidiaries and thereby generate large interest deductions without financing new investment in the U.S.…