Developing countries are losing around $100 billion a year in revenues because foreign investors are channelling profits through offshore zones to avoid tax, a study by U.N. think-tank UNCTAD said on Wednesday. The economic and trade body published the $100 billion figure in its annual World Investment Report, which analyses how much foreign direct investment (FDI) is flowing across borders in search of corporate takeovers and start-up ventures. It calculated the amount by applying an average tax rate of just over 20 percent to around $450 billion of corporate profits shifted out of developing economies every year.