In 1958, Warren Buffett started buying shares in a small map company that he believed was seriously undervalued.
Writing in his 1958 partnership letter, he did not reveal the name of the security, although he did declare that it had an estimated intrinsic value of $135 per share, compared to the market price of $80 at the time, and that he had put around 25% of total partnership assets into the stock.
"While the degree of undervaluation is no greater than in many other securities we own," Buffett stated in his 1958 letter, "we are the...