For the second consecutive year, Des Moines-based EMC Insurance Cos. has been listed as one of the 40 best companies for leaders by Chief Executive magazine. EMC, led by President and CEO Bruce Kelley, ranked 26th this year, up from 35th in 2013. The list was topped by Procter & Gamble Co., IBM Corp. and General Electric Co. Muscatine-based furniture manufacturer HNI Corp., led by Stan Askren, was the other Iowa-based company on the list, at No. 21. The annual ranking is based on a survey of organizations worldwide conducted by Chief Executive. Companies are scored on five criteria: having a formal leadership process in place; commitment of the CEO to leadership development; percent of senior and middle management positions filled by internal candidates; number of companies that report recruiting from the company; and a shareholder performance metric.