(shinogi) as a collection of a feudal tax. The yakuza and its affiliated gangs control drug trafficking in Japan, especially methamphetamine. While many Yakuza syndicates, notably the Yamaguchi-gumi, officially forbid their members from engaging in drug trafficking, some other Yakuza syndicates, like the Dojin-kai, are heavily involved in it. Some Yakuza groups are known to deal extensively in human trafficking. The Philippines is a source of young women. Yakuza trick girls from impoverished villages into coming to Japan, where they are promised respectable jobs with good wages. Instead, they are forced into becoming sex workers and strippers. Yakuza frequently engage in a unique form of Japanese extortion known as sōkaiya. In essence, this is a specialized form of protection racket. Instead of harassing small businesses, the Yakuza harass a stockholders' meeting of a larger corporation. They simply scare the ordinary stockholder with the presence of Yakuza operatives, who obtain the right to attend the meeting by making a small purchase of stock. Yakuza also have ties to the Japanese realty market and banking, through jiageya. Jiageya specializes in inducing holders of small real estate to sell their property so that estate companies can carry out much larger development plans. The Japanese bubble economy of the 1980s is often blamed on real estate speculation by banking subsidiaries. After the collapse of the Japanese property bubble, a manager of a major bank in Nagoya was assassinated, and much speculation ensued about the banking industry's indirect connection to the Japanese underworld. Yakuza have been known to make large investments in legitimate, mainstream companies. In 1989, Susumu Ishii, the Oyabun of the Inagawa-kai (a well-known Yakuza group) bought US$255 million worth of Tokyo Kyuko Electric Railway's stock. Japan's Securities and Exchange Surveillance Commission has knowledge of more than 50 listed companies with ties to organized crime, and in March 2008, the Osaka Securities Exchange decided to review all listed companies and expel those with Yakuza ties. As a matter of principle, theft is not recognized as a legitimate activity of Yakuza. This is in line with the idea that their activities are semi-open; theft by definition would be a covert activity. More importantly, such an act would be considered a trespass by the community. Also, Yakuza usually do not conduct the actual business operation by themselves. Core business activities such as merchandising, loan sharking, or management of gambling houses are typically managed by non-Yakuza