epa08951358 A bitcoin reflects in front of a monitor showing a stock barometer in Duesseldorf, Germany, 20 January 2021. Cryptocurrency Bitcoin has experienced drastic ups and downs in recent weeks and months. At times, its price has increased more than fivefold over the course of the year. The price has risen particularly sharply, by more than 100 per cent since mid-December 2020. However, Internet currencies, of which there are now thousands, are known for their extreme price fluctuations. Regulators, such as the German Bafin recently, therefore repeatedly warn against investing in cryptocurrencies. Recently, the president of the European Central Bank, Christine Lagarde, called for stricter regulation of Bitcoin. EPA/SASCHA STEINBACH