Agriculture thrived on the Midwest's endless prairies, but the exchanges that traded futures on the produce of those prairies the Chicago Board of Trade and the Chicago Mercantile Exchange did not always benefit. Government guarantees set minimum prices for agricultural products, while surpluses prevented prices from rising much. The need to hedge the risk of price fluctuations diminished, and speculation on those fluctuations became unattractive.

Donald MacKenzie, An Engine, Not a Camera, loc. 631