Facebook's vaulting ambition to create a new global digital currency has led it to hold talks with some of America's largest trading houses and cryptocurrency exchanges, including one founded by Mark Zuckerberg's sworn enemies — the Winklevoss twins.

A secretive unit of the social media company has been working for more than a year to create a currency that its 2 billion users can use to send money to each other, and to buy things not just on Facebook, Instagram and WhatsApp but across the internet and in the real world.

"Payments is one of the areas where we have