Worldwide[edit] Aircraft[edit] Boeing and Airbus have a duopoly over the airliner market.[21] General Electric, Pratt and Whitney and Rolls-Royce plc own more than 50% of the marketshare in the airliner engine market.[citation needed] Aircraft tires is dominated by a four firm oligopoly that controls 85% of market share.[22] Finance[edit] Three credit rating agencies (Standard & Poor's, Moody's, and Fitch Group) dominate their market and extend their crucial importance into the financial sector. See Big Three (credit rating agencies). The accountancy market is dominated by PriceWaterhouseCoopers, KPMG, Deloitte Touche Tohmatsu, and Ernst & Young (commonly known as the Big Four)[23] Credit card processing is dominated by Visa and Mastercard.[24] Food[edit] Three leading food processing companies, Kraft Foods, PepsiCo and Nestlé, together achieve a large proportion[vague] of global processed food sales. These three companies are often used as an example of "Rule of three",[25] which states that markets often become an oligopoly of three large firms. Nestlé, The Hershey Company and Mars, Incorporated together make most of the confectionery made worldwide. Technology[edit] Intel and AMD are the only two major players in desktop CPU market worldwide. Microsoft, Sony, Valve, and Nintendo dominate the video game platform market. Nvidia and AMD together make most of the chips for discrete graphics.