For a few days in October 2008, Volkswagen was the most valuable company in the world. Porsche had quietly cornered the stock — controlling about 74% through shares and options — and when short sellers scrambled to cover with almost no float left, VW briefly spiked to around €1,005 a share.

In January 2021, retail traders organizing on Reddit turned GameStop into the ultimate short squeeze. More than 140% of the stock’s float had been sold short; as the crowd bought, the price ran from under $20 to an intraday high of $483, and hedge fund Melvin Capital needed a $2.75 billion rescue after its bet against the stock collapsed.