Shares of several major cryptocurrency companies have experienced significant declines from their historical highs, with some losing up to 95% of their value in recent months. Notable declines include Robinhood (HOOD) down 60%, Galaxy Digital (GLXY) down 65%, and Coinbase (COIN) down 70%. Other companies such as Marathon Digital Holdings (MARA) and MicroStrategy (MSTR) have seen their shares fall by 70% and 80% respectively. The most severe drops were recorded by companies like XXI and BMNR, both down 90%, and SBET, which plummeted 95%.