Volkswagen closed at a record of 304 euros a share Thursday, up 42% since Monday.
The cause of that share performance remains unclear as the two main potential buyers, Porsche Automobil Holding and the German Federal State of Lower Saxony, both ruled themselves out as buyers. Some traders have a theory: the fall of Lehman Brothers Holdings.
Lehman was a big lender of VW stock to hedge funds, traders say. Hedge funds were using borrowed VW ordinary stock to place bets that the shares would fall, part of a so-called short-selling strategy. In the trade, hedge funds sold the borrowed stock in the market hoping the price would fall so that they could repay with lower-priced shares and pocketing the difference. A spokesman for Lehman declined to comment.