Columbia U. Nephrologist Is Tied to Insider Trading

A Columbia University nephrologist has been identified as a central figure in an insider-trading complaint filed by the Massachusetts state securities regulator against a hedge-fund operator. Andrew S. Bomback, an assistant professor of clinical medicine at Columbia, is believed to have told the hedge-fund manager, James A. Silverman, about his work on a new kidney drug made by Questcor, a California company,  The New York Times has reported. Mr. Silverman made about $1.5-million investing in Questcor stock, the newspaper said. Dr. Bomback is not accused of wrongdoing, and a Columbia spokesman told the Times that any university inquiry of the matter would be handled privately.