Brexit politicking risks endangering one of the EU's greatest global success stories, its rulebook governing mutual funds. This could shrink the continent's asset management industry and throw a spanner in the works of one of the region’s vital economic engines.

The regulation, known as Ucits, has been in force since 1985, and allows mutual funds to be sold across borders. One of Europe’s great financial innovations, it has become popular around the world: one-third of Ucits’ €9.4tn in assets are in funds registered for sale outside the European Economic Area. They are particularly popular in the high-growth markets of Singapore, Taiwan, and Hong Kong. This activity supports thousands of EU jobs.