Scarcity of stocks in Volkswagen—after Porsche bought up nearly all the remaining free float—triggered a short squeeze that pushed VW's market capitalization above that of oil major Exxon Mobil at one point Tuesday.
VW shares rose almost 150 percent Monday after Porsche announced Sunday it held stock and options equivalent to 74 percent of Volkswagen. Short sellers then scrambled to cover positions.
On Tuesday, the volatile stock skyrocketed more than 90 percent to above 1,000 euros ($1,248) early in the morning and then closed 73.3 percent higher at 901 euros ($1,125), pushing the DAX index 10 percent up.