The Market Microstructure of the European Climate Exchange

This paper analyzes the market microstructure of the European Climate Exchange, the largest EU ETS trading venue. The ECX captures 2/3 of the screen traded market in EUA and more than 90% in CER. 2009 Trading volumes total ?22 billion and are growing, with EUA transactions doubling, and CER volume up 61%. Spreads range from ?0:02 to ?0:06 for EUA and from ?0:07 to ?0:18 for CER. Market impact estimates imply that an average trade will move the EUA market by 1.08 euro centimes and the CER market 4.29. Both Granger-Gonzalo and Hasbrouck information shares imply that approximately 90% of price discovery is taking place in the ECX futures market. We find imbalances in the order book help predict returns for up to three days. A simple trading strategy that enters the market long or short when the order imbalance is strong is profitable even after accounting for spreads and market impact.