SHANGHAI—Shares of Chinese companies controlled by Zhongzhi Enterprise Group Co., Ltd., founder Xie Zhikun plunged on Monday, after the unexpected death of the rags-to-riches tycoon triggered fears of disorder in a business empire spanning mining to asset management. All nine listed companies controlled by Xie, 61, including education firm Dalian My Gym Education Technology Co., Ltd. and Xinjiang Zhundong Petroleum Technology Co., tumbled in morning trade, even as they say business activities are normal. “Investors fear Xie’s death could lead to internal power struggles and management chaos, so they are dumping stocks,” said Yang Hongxun, an analyst at investment consultancy Shandong Shenguang. The Hong Kong-listed investment holding firm Zhongjin Technology Services Group dropped more than 60 percent, while Shenzhen-listed Success Electronics Co., a maker of liquid crystal display modules, lost 10 percent. Xie died after suffering a heart attack in the capital, Beijing, on Saturday, Zhongzhi said in a weekend …