Free Republic

Tiny gap between private trade confirmations and public data feed can be exploited to detect market moves, critics say Five years ago, the world’s largest exchange operator vowed to fix a flaw in its systems that allowed high-speed traders to infer the direction of the futures market a fraction of a second before everyone else. Now, the defect is back at CME Group Inc.,traders say. And some allege it is yielding rich profits for ultrafast firms at the expense of ordinary investors. The problem arises from the two ways that CME distributes information about a trade. One is the private...