Switzerland's Federal Office for the Environment (OFEV) has set the reduction target for CO2 emissions from large emitters. Companies that operate facilities with high rates of greenhouse gas (GHG) emissions are required to participate to the Swiss trading system for emission allowances (ETS); they are, in turn, exempted from the CO2 tax. The Federal Office for the Environment (FOEN) has defined the key values for the period 2013-2020: the emission ceiling (cap) is set at 5.63 MtCO2 for 55 companies participating in the ETS. This upper limit will be reduced to 1.74% annually until 2020. This ensures that companies also contribute to enable Switzerland to achieve the targets for reducing emissions of greenhouse gases emissions set out in the Act on CO2. The OFEV attributes the majority of free emission rights to companies on the basis of specific reference values sectors. It sets aside 5% for new entrants to the market during the period 2013-2020 as well as for companies that increased their capacity significantly.