Other patent holders are in the business of inventing new "computer implemented inventions" and then commercializing the inventions by licensing the patents to other companies that manufacture the inventions. Walker Digital, for example, has generated a large patent portfolio from its research efforts, including the basic patent on the Priceline.com reverse auction technology. US universities also fall into this class of patent owners. They collectively generate about $1.4 billion per year through licensing the inventions they develop to both established and start up companies in all fields of technology, including software.