It was these two who sold off and caused the big drop!

The early investors sold off the ETH IC0 whale that had been dormant for two years, and sold a total of 10,000 ETH worth $35.39 million. Grayscale also made large-scale BTC transfers, including transferring 422.668 BTC to the Coinbase Prime address and transferring 1788.84 BTC to three new addresses, totaling 2211.5 BTC, worth about $145 million.