THE HAGUE, Netherlands — The Netherlands wants you to know that it is not a tax haven. But Menno Snel, the country’s No. 2 finance official, grudgingly acknowledges that the Dutch have become experts ...

LAST spring, Keith Richards, the craggy-faced and hard-partying lead guitarist for the Rolling Stones, fell from a tree at a beach resort in Fiji, slamming his head against the trunk on his way down.

What the Netherlands has produced a mechanism that may force investors to sell assets simply to fund tax bills on gains that have not actually been realized. There is a simple principle that has ...