The Curious Thomson Reuters Share Price Arbitrage

Does anybody out there still believe in the efficient markets hypothesis? If so, I disprove it thus.

Thomson Reuters is listed both in the UK [LON:TRIL] and in the US (TRI). As CEO Tom Glocer says, "a share in one place is exactly economically equal to another". And yet the shares in New York trade at a whopping 20% premium to the shares in London.

I do understand why this bothers Glocer: It makes a mockery of the idea of a company's stock as a yardstick of its value and performance. But whatever the underlying reasons for this are, they're unlikely to be within Glocer's control. His main task should be running the company: Leave the arbitrage to the hedge funds.