Shares of Swiss banking giant Credit Suisse Group ( CSR) took a hit Friday after the company admitted it overstated its fourth-quarter earnings by $161 million.

The stock, in midday trading, was down 93 cents, or 2.7%, to $33.55.

Credit Suisse said the goof stemmed from an "error in the input data" for accounts in the firm's life and health insurance businesses.

The bank said the accounting mistake would reduce the firm's fourth-quarter profits to $806 million. Full-year profits now total $4 billion.

Overall, the performance of financial stocks on Friday was mixed. The Philadelphia KBW Bank Index largely was unchanged. However, brokerage stocks, as measured by the AMEX Broker Dealer Index, rose 1.6%, outpacing the broader market.

E*Trade ( ET) was the big gainer in the brokerage sector, rising 54 cents, or 4.25%, to $13.24, on news the online brokerage will be added to the S&P 500 index after the close of trading next Wednesday. E*Trade is taking the place of FleetBoston ( FBF), which is being acquired by Bank of America ( BAC).