Rain Lõhmus, the founder of Estonian bank LHV, holds roughly $472 million worth of ether (ETH). But he can't get his hands on the stash because he's lost the private key to access it.

Lõhmus bought 250,000 ETH, worth $75,000 at the time, during the cryptocurrency's initial coin offering (ICO) in 2014. The crypto has been left untouched ever since, a mystery Coinbase director Conor Grogan highlighted on X (then Twitter) in February of this year.

"It's no secret that I have a wallet with 250,000 Ethereum units," Lõhmus said in an interview with Estonian national radio channel Vikerraadio in late October.

He said he hadn't made much effort to retrieve his private key, but will "take all offers" of help.

After the interview, Grogan followed up his post, declaring "one mystery solved." He added that according to his estimation, there is an "absolute minimum" of 886,000 ETH ($1.67 billion) lost forever.

Lõhmus' plight highlights the danger for crypto users that their assets can be permanently lost should they not be able to remember the details needed to access their wallets. Wallet makers have been developing ways to avoid this eventuality, though they have not necessarily proved very popular with the crypto community.

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