NAPERVILLE, Illinois, March 21 (Reuters) - Speculators have drastically shifted their stance in Chicago-traded corn within the last month, selling much more heavily than expected and finally establishing a net short position last week.

The U.S. Commodity Futures Trading Commission on Tuesday afternoon published its Commitments of Traders (CoT) report for the week ended March 14. CoT data has been on delayed release for over a month, but it will be current on Friday if CFTC makes its regularly scheduled publication.

Most-active CBOT futures contracts all traded lower in the week ended March 14, and losses are as follows: corn 2.1%, soybeans 1.4%, wheat 0.3%, soymeal 1.4% and soyoil 4.2%. Corn and soyoil notched multi-month lows during the week and wheat dropped to its lowest level in a year-and-a-half.

Fund selling in soybeans and products through March 14 was underestimated by the market and severely underestimated in corn, though funds unexpectedly bought wheat.

Money managers were net sellers of more than 75,000 CBOT corn futures and options contracts in the week ended March 14, establishing a net short of 54,134 contracts, their first bearish stance since August 2020.

Funds had held a net long of 215,928 corn futures and options contracts on Feb. 21, but they have actively added gross shorts and exited gross longs ever since, resulting in a record three-week sell-off of more than 270,000 contracts on the net – equivalent to 1.35 billion bushels.

Money managers also flipped to a net short in CBOT soybean oil as of March 14, their first since June 2020. The net short was modest at 1,189 futures and options contracts versus the prior week’s net long of 20,526 contracts, and the latest week included an unusually strong entrance of new shorts. In CBOT soybeans, money managers through March 14 shed almost 30,000 contracts from their net long, which fell to 127,661 futures and options contracts. That was their least bullish stance in three months and compares with a net long of about 171,000 in the same week last year.

Unlike in corn, funds have not increased gross soybean shorts, which still remain historically lighter.

Money managers cut their net long in CBOT soybean meal futures and options to 133,970 contracts through March 14 from a record 155,063 a week prior, predominantly on the exit of longs.

However, money managers added fresh longs in CBOT wheat, reducing their net short to 95,257 futures and options contracts from 100,636 a week earlier, which had been their most bearish in more than five years.

In the week ended March 21, which represents the next set of CoT data, most-active CBOT corn futures rose 1.5% and soyoil added 0.1%. Soybeans fell 1.8%, soymeal lost 4.3% and CBOT wheat shed 1.9%.

As of Monday, open interest in futures was higher than on March 14 for corn, but it was lower for wheat, soybeans and soy products. Karen Braun is a market analyst for Reuters. Views expressed above are her own.

(Writing by Karen Braun Editing by Matthew Lewis)