"In most of the successful disruption cases the industry doesn't see what has hit them."
Kristo Kaarmann, one of the founders of peer-to-peer money sending firm TransferWise, has a glint in his eye as he recounts how the business he created with his friend Taavet Hinrikus has grown.
The firm, founded just four years ago, has already moved more than $4.5bn (£3bn) of customers' money across the world and employs 400 people in five offices globally.
Banks once had a near monopoly on this lucrative sector, where people send more than $500bn (£334bn) abroad each year.
But not anymore, according to Mr Hinrikus who says the banks "have fallen asleep".
"They have been quick to adopt modern technology to optimise the way things work internally, but when it comes to services for customers their processes haven't really changed for many decades."
The two Estonians taking on the banks at currency exchange - BBC