Fridays can often be the busiest day of the week for your financial newshounds. As the weekend beckons and financial players start thinking of heading out for the comforts of home, a lot of important news can come out to catch one unawares.

But even by the standards of the “late Friday news event”, last week’s announcement that one of the golden oldies of Swiss private banking, Wegelin & Co, was being sold to a Swiss part of Vienna-headquartered Raiffeisen for an undisclosed amount, was startling. Although some old features may remain, the existence of the Wegelin name as a brand is at an end.

The circumstances are particularly grim. Wegelin, which traces its origins to 1741 in the age of Voltaire and JS Bach, is under investigation by US authorities for allegedly aiding wealthy Americans to evade taxes. And given the fact that this firm is owned by private partners, some of them bearing unlimited liability, the pressure to make a deal and protect legitimate clients must have been enormous.

This saga is also a reminder of how the activities of the US revenue and law enforcement agencies are increasingly forcing foreign banks to make often dramatic moves, such as this one. There are questions to be asked about how far this will go.

To give credit to the partners, they made no attempt to spin the announcement as some sort of brilliant strategic move or use the usual corporate-speak that firms can adopt when trying to explain a move in such conditions. The events surrounding the sale were described by managing partner Konrad Hummler as “extremely painful”.

There remain questions about what will happen to the bank partners, and how much money, if any, they stand to make from the Raiffeisen transaction. One Swiss newspaper claims a substantial sum has been paid but so far the parties concerned have not discussed the issue.

A piece of banking history – for those who care about such matters – has died, although it is not the first case and may not be the last. But if there were any doubts about whether Swiss banks, which together generate about 12 per cent of Swiss GDP, can continue as they are, such doubts are over.

The US, Germany, France, Britain and other countries – perhaps with more than a touch of hypocrisy – are determined to crack Swiss bank secrecy once and for all. As offshore legal expert Philip Marcovici has said in these pages recently, Swiss banking needs to evolve; it is vital that the country’s banks can make a clear distinction between the legitimate need for client privacy and old-style secrecy. If Swiss banks haven’t got the message until now, this sale of Wegelin will surely make sure they do.