According to the circular of the ICE Clear Europe published in September 2009, the clearing house extended the list of permitted cover and included  Emissions Allowances issued under the EU Emissions Trading Scheme (EUAs) and the Kyoto Protocol (CERs).

Clearing Members may now use Allowances or CERs to satisfy original margin requirements. In order to bring a margin, EUAs or CERs should be deposited with a special account of ICE Clear Europe.

So, this proposition and concept presented by the clearing house bases on fiduciary assignment of allowances. It is probably because the other forms of a hypothecation in relation to CO2 allowances are still questionable.