There are several proposed regulations that could significantly broaden the geographic region for NOx allowance trading in the next 2-3 years. Offsets ERC or offset trading has taken place in several U.S. states as far back as the 1980s. ERC transactions are usually complex and must be customized to address a buyer's specific requirements. While there is still uncertainty on whether enough nations including the U.S. will ratify the Protocol in order for it to become binding, there is significant momentum building in the form of voluntary caps and trading of voluntary emissions reductions. Some industrialized nations have already announced domestic GHG emissions control programs that will be implemented over the next couple of years, in advance of the ratification of an international treaty.
Most trading is for the physical commodity itself and physically settled options on coal.