SWISS bank Credit Suisse pleaded guilty on Monday to helping wealthy US citizens avoid paying taxes and agreed to pay about $2.6 billion (£1.55 billion) in penalties.

The settlement resolves a years-long criminal investigation into allegations that Credit Suisse recruited US clients to open Swiss accounts and helped them conceal the accounts from the US Internal Revenue Service.

A Senate investigation found the bank provided accounts for more than 22,000 US clients sheltering up to $12 billion (£7.13 billion). 

Credit Suisse sent staff to recruit US clients at golf tournaments and other events, encouraged US customers to travel to Switzerland and actively helped them hide their assets.

Officials said a criminal charge was necessary because the bank’s misconduct included a lack of co-operation with the investigation and much destruction of documents. 

US Attorney General Eric Holder earlier this month claimed that no financial institution was “too big to jail.”

“A company’s profitability or market share can never and will never be used as a shield from prosecution or penalty,” Mr Holder said. 

“And this action should put that misguided notion definitively to rest.”

But the eventual deal was structured to allow the bank to continue operating, even though Credit Suisse acknowledged it helped clients use sham entities to hide undeclared accounts, destroyed bank records and concealed transactions.

Credit Suisse is on a regulators’ list of 29 “global systemically important banks” whose failure would be considered a threat to the entire capitalist financial system.

The $2.6 billion penalty is roughly equivalent to Credit Suisse’s net income for 2013.