entity according to its role in a particular corporate structure; e.g. holding company, general partner, or a limited partner. Shell companies are a main component of the underground economy, especially those based in tax havens. They may also be known as international business companies, personal investment companies, front companies, or "mailbox" companies. Shell companies can also be used for tax avoidance. A classic tax avoidance operation may utilize favorable transfer pricing among multiple corporate entities to lower tax liability in a certain country; e.g. Double Irish arrangement. A special purpose entity, used often in the context of a larger corporate structure, may be formed to achieve a specific goal, such as to create anonymity. According to a 2013 experimental study where the researchers requested anonymous incorporation in violation of international law, one in four corporate service providers offered to provide services in violation of international law. Examples Shell companies can be used to transfer assets of one company into a new company without having the liabilities of the former company. For example, when Sega Sammy Holdings purchased the bankrupt Index Corporation in June 2013, they formed a shell company in September 2013, called Sega Dream Corporation, into which were transferred valuable assets of the old company, including the Atlus brand and Index Corporation's intellectual properties. This meant that the liabilities of the old company were left in the old company, and Sega Dream had clean title to all the assets of the old company. The former Index Corporation was then dissolved. Sega Dream Corporation was renamed as Index Corporation in November 2013. When Hilco purchased HMV Canada, they used a shell company by the name of Huk 10 Ltd. in order to secure funds and minimize liability. HMV was then sued by Huk 10 Ltd., allowing Hilco to regain assets and dispose of HMV Canada. As another example, the use of a shell company in a tax haven makes it possible to move profits to that shell company, in a strategy of tax evasion. A United States company buying products from overseas would have to pay US taxes on the profits, but to avoid this, it may buy the products through a non-resident shell company based in a tax haven, where it is described as an offshore company. The shell company would purchase the products in its name, mark up the products and sell them on to the US company,