Chicago Climate Exchange (CCX) is the world’s first and North America’s only voluntary, legally binding greenhouse gas (GHG) reduction and trading system for emission sources and offset projects in North America and Brazil. CCX employs independent verification, includes all six greenhouse gases, and has been trading greenhouse gas emission allowances since 2003. The Chicago Climate Exchange (CCX) lists its own quality of voluntary credit called a CFI. These can be bought and sold on the exchange.