Shares of the largest mining companies are showing a sharp decline in prices as the halving in the Bitcoin network approaches, following which on April 20 the reward for mining blocks and the volume of new coins entering circulation will be halved. Thus, the securities of Marathon Digital (MARA) and Riot Platforms (RIOT) have fallen in price by 16 and 17%, respectively, over the past five days. Investment firm Valkyrie's WGMI exchange-traded fund (ETF), which tracks miners, fell 11.2% over the same period, according to TradingView.