Hot weather may wipe out investors' bets on record US corn crop

Chicago

INVESTORS betting on a record US corn crop are about to get a closer look at yields - and they may not like what they see.

Hot weather across the US corn belt in June and July came during critical periods of ear development. That's bad news for money managers that have been increasing their bets on declines for prices. Ear weights may not live up to expectations, tightening the supply outlook. Futures in Chicago last week capped the biggest gain in two months.

To understand why prices are rallying, look no further than Tony Heiden, an agronomist for 660 Agronomic Analysis who farms 600 acres near Winona, Minnesota. Yield estimates for his clients have shrunk because of the summer heat. Ears lost a…