IBM ( IBM), known by many on Wall Street by its nickname "Big Blue," was regarded by the last two generations as a computer hardware company. It made money for investors for decades by manufacturing hardware and software for large mainframe computers. Then, in the 1980s, IBM pioneered the personal computer. Its big mistake was focusing on the hardware and allowing Microsoft ( MSFT) to engineer and control the operating system. Now IBM is focused entirely on information technology consulting, systems integration and software. The stock is trading at an all-time high and is the largest constituent stock in the Dow Jones Industrial Average. However, given that IBM is a service business, it is able to leverage low single-digit sales growth with its high gross margins into low double-digit percentage earnings growth. IBM shows up on recent lists of 10 Longest-Held Stocks of Top-Rated Mutual Funds and 18 Stocks That Will Outlive the Hype.