Memristors is not a solo business. In a recent SyNAPSE-centric meeting, Robert Thijs Kozma brought up a very interesting post on the rapidly changing business landscape of memristors. A number of companies beyond Hewlett Packard, including AMD, Axon Technologies, Energy Conversion Devices, Micron Technologies, Samsung, and Sharp have been very active in researching, and patenting, memristor-based devices. An excellent outlook of the business and patent landscape around variations on the memristor theme can be found here.