CHICAGO (AP) — An accounting investigation is under way at Archer Daniels Midland and the top financial executive at the agribusiness giant has been placed on administrative leave. The company postponed the release of its annual and quarterly financial reports that were scheduled for Tuesday and shares of the Chicago company tumbled 24% on Monday. ADM said that an investigation was initiated in response to a voluntary document request by the U.S. Securities and Exchange Commission. The company said late Sunday that it’s cooperating with the SEC. ADM named Ismael Roig as interim chief financial officer. Roig joined Archer Daniels Midland in 2004. ADM said it’s working with outside counsel and the audit committee of the company board to complete the investigation quickly.