Small bakeries say speculators are raising food costs and urged the U.S. futures regulator to curb trading by funds and other big investors.

“As bakers, we do not pretend to know the complex and sophisticated rules and practices of the commodity markets,” said the Independent Bakers Association in a letter to the Commodity Futures Trading Commission.

The bakers said they believe funds have raised prices and made markets more volatile.

“We would like the law of supply and demand in the free market to function without the injection of billions of dollars by persons who have no need or reasons to buy an agricultural commodity,” said the group, which represents mainly family-owned wholesale bakeries.

The CFTC is weighing new limits on speculative positions, although it has proposed existing limits stay for wheat. Speculators are now limited to 6,500 wheat contracts, but bakers said 800 contracts would be better.