Kristo Käärmann
As a consultant living in London in 2019, Kristo Käärmann made what he called an “incredibly stupid” decision; he tried to send his Christmas bonus back home to Estonia.
Käärmann said the transfer cost him around £500 because of the interest rate used by the bank. So he struck a deal with fellow Estonian Taavet Hinrikus, who was paid in euros but needed pounds: they would send each other money instead of trying to change currency.
In 2011, the pair formed a company built on that workaround — Transferwise, which later became Wise.
Even after Wise made him a billionaire, Käärmann hasn’t been immune to costly personal finance blunders. He was fined £366,000 in 2021 after appearing on HMRC’s list of deliberate tax defaulters, which a Wise spokesperson said was because he forgot to file his taxes.
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