J.C. Penney Co. fell the most in a month after announcing president Michael Francis was leaving in the aftermath of a marketing strategy that flopped with shoppers. The retailer said Francis stepped down after joining the company in October. The company didn’t give a reason for his exit. Chief executive Ron Johnson, who is taking over marketing and merchandising, is trying to remake the retailer’s image and overhaul its pricing strategy. Francis was serving as marketing chief at Target Corp. when Johnson hired him. In January, Johnson unveiled his four-year plan to transform J.C. Penney into America’s favorite store. Johnson also has sought to replace J.C. Penney’s relatively high-list prices — which it aggressively discounted — with lower everyday “fair and square” pricing.