CME spokeswoman Anita Liskey said there were "times when customers experience a latency of a few milliseconds between the time they receive their trade confirmations and when the information is accessible on the public feeds," she said.
She also said the latencies were "not consistent and vary across asset classes."
But computer trades made in the blink of an eye can result in a privileged class of traders -- those with high-speed computers -- taking advantage of information the public has yet to see, The Wall Street Journal reported Wednesday.
The difference is measured in milliseconds -- in a range between 1 and 10 milliseconds in which computers recognize price changes and shift buy and sell orders accordingly, the Journal said.
A millisecond is one-thousandth of a second.
Further, traders are given advanced notice of their own trades among the 12.5 million futures contracts a day the Chicago Mercantile Exchange, on average, handles a day, the Journal said.
That means traders are provoking the price changes themselves. Their computers then react to the information they have that nobody else would have.
The practice gives traders an "informational advantage," said finance Professor Peter Kyle at the University of Maryland, who is also a former member of the Technology Advisory Committee at the Commodity Futures Trading Commission.
One method of taking advantage of the lag time is to post a buy or sell order that is triggered by a price change. If the order is just pennies away from the current price, confirmation of the order is the equivalent of an early indication that the price has gone up or down.
If the price of a commodity is at $100 and an order to sell at $100.02 is posted, then a computer that recognizes first that the sell order has gone through is the equivalent of a few seconds of insider information.
It's like buying an early boarding pass at an airline and then taking advantage of the fact that nobody but yourself knows, if only for a second, what the in-flight movie will be.
Kyle said the practice constituted "a tax on other traders" because "you get all the gains from being the first guy" to make a trade.