The short interest in Lehman Brothers stock has reached a record of 13% of the outstanding stock, the Financial Times reported, the highest level among Wall Street banks. David Einhorn, founder of Greenlight Capital, has recently criticised aspects of Lehman's financial reporting.

Einhorn recently published a book, Fooling Some of the People All of the Time, on his long-running and contentious short bet on Allied Capital, a private finance group. Greenlight invests both long and short.

• Einhorn speech on Lehman
• Lehman investor relations