Spotlight on Goldman as commodities hearings begin

By Moming Zhou, MarketWatch

NEW YORK (MarketWatch) -- Goldman Sachs Group, already under fire for reaping record trading profits in the aftermath of the financial crisis, is now fighting to defend one of its biggest sources of revenue -- commodities trading -- with regulators considering setting limits on Wall Street speculators. 

Representatives of the firm, along with those of other big investment banks, are scheduled to appear at a series of hearings held by the Commodity Futures Trading Commission starting Tuesday -- part of the Obama administration's biggest move yet to clamp down on commodities speculation, which has roiled the prices of everything from oil to corn and wheat in recent years. 

At issue for Goldman Sachs is a major exemption it enjoys from limits on trading in certain types of agricultural commodities. Such an exemption is usually reserved for traders classified as "hedgers," such as farmers or food producers who depend on stable prices for their businesses.