Xerox Corporation
Xerox has been called the company that “fumbled the future.” Their Palo Alto Research Center (always known as Xerox PARC) was the place where the graphical user interface, the mouse, Ethernet, the laser printer, the first portable computer and many other significant developments took place.
The company ignored these advances (to be fair, so did many others). They entered the large computer business in 1969 with the purchase of Scientific Data Systems (SDS) but this was not a successful venture and Xerox closed its computer division in 1975.