Kristo Käärmann Kristo Käärmann is an Estonian businessman. is an Estonian businessman. Käärmann was a financial consultant for the Wise Wise (formerly TransferWise) is a London-based financial technology company founded by Estonian businessmen Kristo Käärmann and Taavet Hinrikus. (formerly known as TransferWise) company which he founded together with Taavet Hinrikus Taavet Hinrikus is an Estonian businessman. .