CME Group Inc. (CME) will begin incorporating electronic trades into settlement procedures for corn, soybean and livestock futures in the spring, the exchange announced Monday in the latest sign of the growing dominance of screen trading.

The exchange currently bases settlements for corn, soy, cattle and lean hog futures on activity in the trading pits in Chicago, even as volume has largely migrated to the exchange's electronic trading platform, Globex. The exchange's new approach will incorporate both floor and Globex activity, the exchange said in a statement. It said it would provide more details early next year, and implement the changes in March or April.

Meanwhile, settlements in wheat and rice futures, which are already based exclusively on Globex activity, will now incorporate floor activity as well.

Floor traders say pit settlements have played an important role in keeping some traders on the trading floor. But electronic traders argue that it makes more sense to base settlements on Globex activity since electronic trade volume dwarfs pit trading activity.

But the changes are unlikely to have a dramatic effect, said David Smoldt, vice president of operations for brokerage FCStone. He said many customers still want to executive spread trades, in which a trader simultaneously buys one contract and sells another. Many options traders also prefer the trading floor, particularly for complicated options trades, Smoldt added.

Smoldt said the trading floor will remain active as long as there is the liquidity to execute such trades.

"If you don't have the liquidity it will all go to the screen sooner or later," Smoldt said.

It was unclear how the changes could affect the settlement time for livestock futures. Live cattle, feeder cattle and lean hogs currently settle based on pit trading at 2 p.m. EST, but those markets continue to trade electronically until 5 p.m. EST. A CME spokesman couldn't be reached for comment.

It would be "foolish" to continue basing settlements on pit trade given its relatively small volumes, said Michael Gorham, a former CME Group executive and director of the Center for Financial Markets at the Illinois Institute of Technology.

But he added that traders have long predicted the "final nail in the coffin" for pit trading, only to be proven wrong.

"I stopped predicting it years ago," he said.

In the livestock markets in particular, many of the traders and their customers are older, and resistant to change, he added.

Floor trading has consistently lost volume to Globex in recent years. For all CME products, pit volume in November was down 17% versus a year ago, compared to only a 7% decline in Globex volume.

The changes are subject to regulatory review by the Commodity Futures Trading Commission, the exchange said.

-By Ian Berry, Dow Jones Newswires; 312-750-4072; ian.berry@dowjones.com