maintains a nationwide railway network as well as common ticketing rules that it inherited from JNR. Passengers may travel across several JR companies without changing trains and without purchasing separate tickets. However, trains running across the boundaries of JR companies have been reduced. JR maintains the same ticketing rules based on the JNR rules and has an integrated reservation system known as MARS (jointly developed with Hitachi). Some types of tickets (passes), such as Japan Rail Pass and Seishun 18 Ticket, are issued as "valid for all JR lines" and accepted by all passenger JR companies. Ownership In 1987, the government of Japan took steps to divide and privatize JNR. While division of operations began in April of that year, privatization was not immediate: initially, the government retained ownership of the companies. Privatization of some of the companies began in the early 1990s. By October 2016, all of the shares of JR East, JR Central, JR West and JR Kyushu had been offered to the market and they are now publicly traded. On the other hand, all of the shares of JR Hokkaido, JR Shikoku and JR Freight are still owned by Japan Railway Construction, Transport and Technology Agency, an independent administrative institution of the state. All the JR Group companies operating in the Honshū region are constituents of the Nikkei 225 and TOPIX 100 indexes. Background The demise of the government-owned system came after charges of serious management inefficiencies, profit losses, and fraud. By the early 1980s, passenger and freight business had declined, and fare increases had failed to keep up with higher labor costs. What remained of the debt-ridden Japanese National Railways after its 1987 breakup was named the Japanese National Railways Settlement Corporation. Its purpose was to dispose of assets and debts not absorbed by the successor companies and to execute other activities relating to the breakup, such as outplacement of former personnel. The new companies introduced competition, cut their staffing, and made reform efforts. Initial public reaction to these moves was good: the combined passenger travel on the Japan Railways Group passenger companies in 1987 was 204.7 billion passenger-kilometers, up 3.2% from 1986, while the passenger sector previously had been stagnant since 1975. The growth in passenger transport of private railways in 1987 was 2.6%, which meant that the Japan Railways Group's rate of increase was above that of the private-sector railways for the first time