Shares of J.C. Penney Company Inc. (NYSE: JCP) plunged mid-Tuesday by 10.15 percent, or $2.47, to $21.86 in the wake of President Michael Francis' departure, as the department store struggles to change its discount model and increase revenue.

Plano, Texas-based J.C. Penney poached Francis from Target Corp. (NYSE: TGT) in October, following the ascension of CEO Ron Johnson, the former retail chief of Apple Inc. (Nasdaq: AAPL). But Francis resigned abruptly Monday, following J.C. Penney's report of a $163 million loss and 20 percent fall in sales during the first quarter of the year.

Francis will earn a total of around $15 million in salary, sign-on bonus and severance, according to the Wall Street Journal. Johnson and hedge fund mogul Bill Ackman of Pershing Square Capital Management LP, which owns 16.5 percent of the company, could lose big if the stock keeps sliding. Johnson has the potential to earn hundreds of millions of dollars through his 7.26 million shares of restricted stock, but if the price stays below $29.92 after six years, he will lose $50 million.