According to @EmberCN, a whale that received 67,000 ETH from the Ethereum Foundation address in 2015 transferred 15,200 ETH ($56.47M) to Kraken at 2 AM on June 8. This large transfer might have contributed to ETH's price drop today. The whale's ETH originated from two sources: 200,000 ETH from the Ethereum genesis block (likely from ICO participation) and 67,000 ETH from the Ethereum Foundation address.