Why Am I Being Asked to Fill Out a US Tax Form in London?

Imagine this: you’re a perfectly respectable UK company, opening an account with a perfectly respectable UK prime broker, when suddenly you’re handed a document called a W-8BEN-E. The name alone sounds like something dreamt up by a malfunctioning robot. You blink at your broker. “But… we’re in London. Why on earth do I need to complete a US tax form?”

It does feel absurd. You’re not a US company, you don’t pay US corporation tax, and your broker is just round the corner from Pret. But the explanation lies in a quirk of US tax law – a quirk that likes to follow its money around the globe.