LIMASSOL, Cyprus — Andreas Marangos, a Porsche-driving lawyer here, had just woken up when he heard the news that threatened to destroy his and Cyprus’s most lucrative business: setting up shell companies and providing financial services for wealthy Russians.

He rushed to his computer to check whether the “crazy talk” he had just heard was true — that his government had agreed last week to effectively confiscate 9.9 percent of the wealth of anyone holding more than 100,000 euros, about $129,000, in a Cyprus bank.

A week later, this Mediterranean island nation is still trying to figure out how to raise the $7.5 billion European lenders say it must have by Monday in return for a bailout. Late Saturday, the tentative plan was to seize a portion of all deposits above 100,000 euros, with the bite set at 20 percent for those banking with Cyprus’s biggest bank.

For Mr. Marangos, either plan is bad news.

“Since last Saturday, we are just answering calls from angry clients,” said the lawyer, whose firm has helped Russians and Ukrainians set up 6,000 companies in Cyprus so that they can avoid taxes, benefit from a sound legal system and, they hoped, keep their money safe. Cyprus still offers those draws, he insisted, but his clients “thought we had betrayed them.”