Millions of hidden U.S. trades were revealed for the first time last December when a new SEC rule took effect. For the first time, odd-lot trades—those with fewer than 100 shares—appeared on the consolidated order book. That means information on those deals is available to everyone, not just investment banks and sophisticated traders.

Odd lots | Problems
What happened? December 9, 2013

Sources: “What’s Not There: Odd-Lots and Market Data” (Journal of Finance, 2014) by Maureen O’Hara, Chen Yao and Mao Ye; Mark Yamada; SEC; Consolidated Tape Association.

Facts | Big names, Big effects

*Data not yet available for trading since the SEC’s latest rule took effect.

Jessica Bruno is content editor at Advisor Group. Reach her at or on Twitter, @JessicaNBruno.

Originally published in Advisor's Edge

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