Einhorn created his fund in 1996 and has since grown it significantly to where Greenlight is one of Wall Street's most successful and visible funds. Due to his frequent speeches
Einhorn has gained notoriety in recent years for his outspoken criticism of modern accounting practices at investment banks and financial institutions all the while holding accompanying large short positions in the targets of his criticism. He successfully battled Allied Capital over a number of years, a battle he chronicled in his book Fooling Some of the People All of the Time: A Long Short Story.
More recently Einhorn has targeted Lehman Brothers. Lehman's, noting the failure of Allied smear counter campaign in discouraging Einhorn, instead tried to silence him by sharing information with him a private tele-conference in early-mid 2008. To Lehman's dismay Einhorn was not only not convinced he then proceeded to disparage the company publicly in a speech given about his book. In mid September 2008 Lehman Brothers filed for bankruptcy after a prodigious 90%+ decline in their stock price since the beginning of the year.