Credit Suisse First Boston slumped to a net loss of nearly $1bn (€1.13bn) in 2001 after restructuring costs, Enron, Argentina and regulatory action wiped out the firm's already meagre profits in the first part of the year.

The losses mark the worst performance of any of the big investment banks during the difficult market conditions in 2001, and cap a dreadful year for CSFB. The losses were almost all incurred in the fourth quarter, when CSFB made a net loss of $1bn. The final net loss for 2001 of $961m means that the investment banking business struggled to make $30m in profits in the first nine months of the year.