from wsj: Goldman Sachs Group Inc. is considering shutting down one of the world's largest private stock-trading venues, according to people familiar with the matter. In conversations with market participants over the past several months, Goldman executives have broached the subject of closing its so-called dark pool trading operation, known as Sigma X, the people familiar with the matter said. Goldman executives are weighing whether the revenue the firm generates from operating Sigma X is worth the risks that have been highlighted by a series of trading glitches and growing criticism of dark pools, the people said. No decision is imminent, and Goldman could keep the business, according to people familiar with the discussions. http://online.wsj.com/news/articles...0001424052702304819004579490030481110264.html