Almost one month after the stash went missing Thomas T. has raised the reward on offer from 40,000 francs to 135,000 francs, the 20 minutes website reported.
Since the story became public, the Lucerne resident says he has been swamped with emails from people wishing to claim the reward – but no one has been able to return the cash.
The 27-year-old lost the currency in the city of Lucerne on April 9th after he removed the bag – stamped with a Lionfood logo – from a bank safe to make some transactions.
After driving to Lucerne train station he parked opposite the Swisscom Shop before going shopping at a Migros supermarket.
He is unsure whether he left the bag containing the Keepkey and Ledger Nano S data devices in his car or elsewhere.
He also lost the storage devices and has no access to online backup because he does not have the necessary recovery codes.
No one apart from the owner would be able to access the digital currency as both are PIN-protected with the number of access attempts limited.
Anyone with information about the missing bag is asked to email firstname.lastname@example.org.