RPX Corporation (NASDAQ:RPXC) purchases and owns patents and then licenses them out to operating companies. RPX's customers are technology companies which pay a subscription to be allowed to use the license and to be protected from patent litigation. PRX purchases a broad range of patents and patents which may overlap with existing patents they own. This allows RPX to avoid the chance of litigation over licensing a patent whose process is similar to another patent. RPX does not use any of its patent to begin litigation against any of its clients.
RPX capitalizes on the high number of technology patents, many of which overlap in content. This high overlap makes operating companies susceptible to patent infringement litigation. As a result, companies must spend time researching potential patent infringements and defending against actual ones. RPX's patent assets (patents which they have purchased) allows its customers which are licensed by RPX to minimize such risks. 
The company's initial public offering of stock on the NASDAQ occurred on May 3, 2011. The company offered 8.43M shares each for $19. This was above the high end of the price range of $16-$18. The deal had originally been announced for 7.3M shares. The final deal was $160M, which was $36M greater than what the deal had originally been. The lead underwriters of the deal were Goldman Sachs Group (GS) and Barclays (BCS).
For the full year 2010, RPX reported a total revenue of $94.9M and a net income of $13.9M. Both were an increase over the 2009 revenue and income figures.