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 specialize in inducing holders of small real estate to sell their property so that estate companies can carry out much larger development plans. Japan's 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 recognised 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 members who pay protection fees for their activities. There is much evidence of Yakuza involvement in international crime. There are many tattooed Yakuza members imprisoned in various Asian prisons for such crimes as drug trafficking and arms smuggling. In 1997, one verified Yakuza member was caught smuggling 4 kilograms (8.82 pounds) of heroin into Canada. Because of their history as a legitimate feudal organization and their connection to the Japanese political system through the "uyoku dantai" (extreme right-wing political groups), Yakuza are somewhat a part of the Japanese establishment, with six fan magazines reporting on their activities.