Something changed in the United States late last December with the new tax laws that amount to a wholly fresh approach to the way that it approaches companies and individuals. It's a transition so fundamental, and yet it is not clear if its wider implications have been fully appreciated in Asia.

The headlines outside the US have focused largely on two elements of the Tax Cuts and Jobs Act. The dramatic cut in the corporate income tax rate from a top 35 per cent to a flat 21 per cent has got the most attention. To a lesser extent, so too has the change from a worldwide tax system to a so-called territorial one.