It's been a rough few weeks for investors betting against Tesla, one of the most-shorted stocks in the United States. Tesla stock has rallied almost 17 percent since the company's early June annual shareholder meeting at which Chairman and CEO Elon Musk promised profitability in the third quarter. Shares kept trending higher this week, rising slightly after Tesla announced plans to lay off 9 percent of its workforce. Musk added $25 million worth of shares to his personal holdings.