In a frank opinion column for The New York Times, Greg Smith, a Goldman Sachs executive, explained on Wednesday why he was resigning from the firm.

Mr. Smith, who was head of Goldman’s United States equity derivatives business in Europe, the Middle East and Africa, said clients’ interests were sidelined in how the firm operated and thought about making money. Mr. Smith placed the blame for this cultural change on top management, including Goldman’s chief executive, Lloyd C. Blankfein, and its president, Gary D. Cohn.