Greenlight's David Einhorn slams Tesla in a recent investor letter. : "The wheels are falling off — literally," Einhorn, founder and president of Greenlight Capital, said in an investor letter seen by CNBC. Einhorn's public bet against Tesla added to the fund's 11 percent gain in the first quarter. The 50-year-old investor slammed Tesla's safety protocols and cars with faulty suspensions, "such that the wheels sometimes fall off (referred to as 'whompy wheels')." He cited an incident in February when a man in Florida was killed in his Model S after hitting a tree.