Executives of the Chicago exchanges and many market experts said that this agreement made legislation unnecessary.

The Chicago exchange has rolled out an electronic trading system of its own for some trades.

A trading executive at a Chicago exchange, on last week's indictments.

And that is probably not a bad thing in the view of the Chicago exchange, which has other issues to address.

Prosecutors are said to be using documents from the Chicago exchanges' disciplinary proceedings to help build their cases.

The Chicago exchanges charge members between 20 and 50 cents per contract for each of those 220 million contracts that they trade.

After 40 minutes of eerie silence, the Chicago exchange reopened.

"Now, the viability of the Chicago exchanges depends upon how quickly they can adapt."

"If this is allowed to go untouched, the rules have no meaning," a trader on the Chicago exchange said.

The Chicago exchanges have reacted swiftly to competition in the past.