InterDigital is probably one of the most well-known royalty revenue companies. Its portfolio consists of approximately 18,000 patents ranging from 2G and 3G to 4G LTE and 802.11 technologies. In June, InterDigital sold 1,700 of its 3G and 4G LTE wireless patents to Intel for $375 million. According to company estimates, it should be able to replace these 1,700 patents with new discoveries within 18 months. Based on the rough price of $221,000 per patent, InterDigital's patent portfolio alone could be worth around $4 billion if it were sold (compared to its current market cap of $1.4 billion). Although royalty revenue is only guaranteed if InterDigital's wireless solutions are utilized, the company managed to produce $302 million in royalty revenue in 2011 and appears to be destined for more patent sales in the future. InterDigital (Nasdaq: IDCC) Source : http://www.fool.com/investing/general/2012/08/16/5-companies-you-can-treat-like-royalty.aspx