2015 a standout year for wheeling and dealing

OF all the ways to describe mergers and acquisitions in 2015, "plain vanilla" is not one of them.

Last year was one for the record books, generating US$4.7 trillion in announced deals, with the highest percentage ever derived from those valued at more than US$5 billion, according to data compiled by Thomson Reuters.

Unlike boom years past, however, this one was characterised by dozens of complex and creative financial structures. Drugmakers Pfizer and Allergan sought to combine effectively through a tax-inversion deal, lowering Pfizer's tax rate. Dow Chemical and DuPont, two storied chemical giants, agreed to merge into a US$130 billion behemoth with the explicit intent to be separated into three companies in a few years.