The Commodity Futures Trading Commission's expected announcement this week of new oversight initiatives in the agriculture-futures markets, coming on the heels of a similar announcement last week on energy markets, is a turning point for the historically free-market-oriented agency.

Over the past two years, the CFTC has repeatedly rebuffed critics who contended that an influx of new pension-fund and hedge-fund investors is changing the way the commodity markets operate. Saying they could drill into trading data that others outside the regulatory agency can't see, the agency's economists repeatedly said that speculation in the commodity markets was unrelated to the increase in prices for everything from oil to wheat and corn.