TransferWise is all about converting currency from one form to another, a process that pretty much always requires a bank's participation. That means a bank will take a percentage of the total transfer as commission and will even alter the conversion rates such that it earns money for itself in the process.
In the currency-transfer world, the banks make their money coming and going.
When Käärmann needed to buy some British pounds, he decided to go around the banks and teamed up with a friend in the U.K. who needed euros. Käärmann sent his euros to the U.K., and his friend sent British pounds back to him. It was a completely analog arrangement, sure, but Käärmann and his friend had full control of the process, and after carrying out this process a number of times over two years, they were able to save $15,000 in bank fees.
So Käärmann pushed the idea further and formally co-founded TransferWise, a startup that helps automate transactions like the one above. The TransferWise web site allows people to create payment transfers in their own currency to TransferWise, which completes the transaction abroad with the person you're sending money to in local currency, without the usual commissions.
It's currency conversion that completely circumvents the banks, no foreign friendships required.
Firing on all cylinders as a proper startup for two and a half years now, the company has saved its customers $15 million in bank fees to date, Käärmann says.