Commodity prices are ending 2011 with a whimper. Over the year as a whole the only major commodities to show significant increases are Brent crude and gold. Most components of the closely-watched S&P GSCI index have seen large falls, including declines of 20-30% in the prices of key industrial metals and agricultural commodities. This highlights the importance of macroeconomic and financial factors in driving prices, making for a rollercoaster ride.