US stocks were mixed on Friday but were set to break their longest run of weekly losses in four years after Citigroup posted better-than-expected earnings, offsetting some poor results from Google, Microsoft and Merrill Lynch.

Citigroup, the biggest US bank by assets, said it lost $2.5bn in the second quarter after about $7.2bn of writedowns. That was a smaller loss than the $3.67bn analysts were expecting. Citigroup shares jumped 7.7 per cent to $19.35.