Swiss bank Credit Suisse could announce the loss of up to 5,000 jobs in its investment banking business at its forthcoming first-quarter results, Reuters reported citing a Swiss newspaper.

Citing an estimate from a member of senior management, the Sonntag newspaper said the bank could cut around 5,000 positions. The investment bank is "simply completely oversized", the person was quoted as saying.

The bank is due to report first-quarter results on April 25.

Credit Suisse ended 2011 with 20,900 investment bankers, 200 more than at the beginning of the year. Staff count at the whole bank was largely stable even after two rounds of cuts eliminated 7 percent of the bank's overall workforce, or 3,500 jobs.

The Zurich-based bank has faced increased shareholder criticism about the size and the cost of its investment bank, raising pressure on Chief Executive Brady Dougan for cutbacks.