The story began in 2010, with two friends, Kristo Käärmann and Taavet Hinrikus, both from Estonia living in London. One was a Skype employee who got paid in Euros. The other got paid in Pounds, but had a mortgage in Estonia that had to be paid in Euros. They were spending money they didn't need to on their financial transfers, so they devised a beautifully simple workaround. One that became a billion-dollar business. Each month, they checked Reuters for a good mid-market rate. Kristo put Pounds into Taavet's UK bank account, and Taavet topped up his friend's account with Euros. Both got the currency they needed, and neither paid hidden bank charges. Today, using similar principles, TransferWise makes sending money abroad faster, more convenient and up to eight times cheaper than the high street banks.