Back in 1923, a young Benjamin Graham noticed that DuPont owned a large number of shares of General Motors and strangely, the market value of DuPont was about the same as its stake in GM. In spite of the fact that DuPont was a highly profitable firm, its stub value was close to zero. Graham made the smart trade, buying DuPont and selling GM short, and made a bundle when the price of DuPont went up.
