In mobile communication the mobile termination service involves charges between Mobile (Virtual) Network Operators (MvNOs). Furthermore, only the MvNO of the callee is able to terminate his calls. Thus, in the MvNOs call-termination market there is only one player profiting from Mobile Termination Rates (MTR); in turn this market is considered by regulators to be a "de-facto" monopoly, since the early days of the introduction of commercial mobile communication services. Given this monopoly fact, the only solution against a potential speculation by MvNOs was the regulation of the MTR. In a monopoly there is a corporation that is the only seller of a good or a service, and thus it can define the price. However, monopolies can be divided into two categories, the naturally defined and the market-defined monopolies. The power market in many countries is considered to be a natural monopoly, and the main reason is that there is usually only one power-wire reaching each house. Thus, only the company that owns the delivery network can provide power services. The termination service in mobile communication until the 4G is also considered to be a monopoly. However, this is a market-defined monopoly, since there is no physical limitation (e.g., wires) for reaching a mobile user.