Once mined, Bitcoins can, like securities and currencies, be traded on special trading platforms outside of the usual stock exchanges and Forex platforms. After registration and logging into the respective trading center, users can then exchange either their own mined and acquired Bitcoins into "genuine" currencies (euro, dollar, yen, etc., referred to as fiat currencies) or purchase Bitcoins from other users. The exchange rate for the exchange of Bitcoins into fiat currencies by supply and demand: If more market participants want to buy Bitcoins than others want to sell them, the price rises. If the pressure to sell is greater than the interest of potential buyers, the price falls. In practice, the prices quoted on different trading platforms frequently differ significantly despite being quoted at the same time.
The business model of Bitcoin exchanges consists mostly of imposing exchange fees for purchases and sales – generally in the amount of a small percentage of the transaction volume. The increasing interest in alternative currencies and the rising volume of transactions allow providers to achieve a solid profit despite mostly moderate fees.
Exchanges that are active in Germany are subject to regulation by BaFin and as a rule require a BaFin license of their own or else carefully designed cooperation with a bank partner, under the liability umbrella of which they can then slip through as a "contractually tied agent." The legal requirements of such a liability umbrella design are very high, the required contract design extremely complex and in the end not without a residual risk for the parties concerned.