Swiss bank USB has announced it is cutting 3,500 jobs worldwide, in the bank's latest effort to save $2.5 billion annually by 2013.

USB's investment bank unit will see 1,600 jobs eliminated – about 45 percent of the total expected job cuts. The banking giant has 65,000 worldwide employees located in more than 50 countries.

USB says many of the job cuts will happen through natural attrition and site closures.

A company statement says the cuts designed to improve operating efficiency.