Credit Suisse says it's cutting roughly 4,000 jobs to reduce costs after announcing a massive pre-tax loss in the fourth quarter that includes "substantial charges which are not reflective of our underlying business performance."

The Swiss banking giant posted a net loss of 5.3 billion Swiss francs ($5.3 billion), compared to a net profit 691 million francs a year earlier. It reported a pre-tax quarterly loss of 6.4 billion including a 3.8-billion-franc impairment charge linked to its acquisition of Donaldson, Lufkin & Jenrette investment bank in 2000.

CEO Tidjane Thiam said the job cuts will represent savings of 1.2 billion francs per year. In the fall, Thiam outlined plans for staff reductions but Credit Suisse had not specified the number.

Revenues fell 34 percent to 4.2 billion francs.