Lei Jun Xiaomi Corp. founder Lei Jun’s purchase of about HK$100 million ($12.9 million) worth of company stock may help bolster sentiment in the smartphone maker after shares tumbled more than 30% from the July peak. The announcement, disclosed late Monday, lifted Lei’s stake to 23.26%, and sent shares rallying 4.4%, the biggest one-day jump in two months. Analysts say the move, which is unusual as it involves the founder instead of just the company, underscores efforts to stabilize the stock and limit d ...