From HuffPo: A small band of humans is fighting what it warns is the rise of the machines in financial markets. A group of two dozen brokers and traders has sued CME Group, the owner of major commodities exchanges in New York and Chicago, arguing that a new rule that took effect on Monday would benefit high-frequency traders, favoring machines over people and putting hundreds of jobs at risk at futures and options exchange the Chicago Board of Trade.
Under the current trading system, the final prices for futures contracts for everyday commodities like corn and soybean oil are negotiated in person, on the floor of the exchanges in an area known as the "pit." This "outcry market system," as it is known, is responsible for the noisy, frantic trading environment -- in which brokers and traders yell and hand-signal buy and sell orders with one another -- that many still associate with the floors of stock exchanges. Some of the customers that these traders and brokers work for are farmers looking to hedge the price of various crops.
The CME's new rule replaces this in-person trading process with a blended system that takes into account orders placed by computerized traders when arriving at a final settlement price for these contracts. According to the lawsuit, this change "will, for all practical purposes, eliminate the open outcry pit based system..."