Murky business

Buying 25,000 shares of a thinly traded company might not sound like a perilous task, but Joe Saluzzi, co-head of equity trading at New York-based brokerage Themis Trading, tells a different story. The world he describes is one in which he is being constantly watched, tracked by lightning-fast predators, and has to tread very carefully.

To illustrate, he outlines a scenario where he has been asked to fill an order on behalf of an institutional investor. The stock is bid at $12.22 and, looking at