Just a fortnight ago, a Whale saw an opportunity in the ETH dip and decide to buy over a 100k ETH and stake them all at $4.1k; another sold his BTC and opened a long position for ETH on an exchange. Then suddenly the floodgates opened and more Whales began "dumping" to buy more ETH. Any obvious reason for the flow of liquidity into ETH? Be my guess!
While others were busy analysing the market, these guys acted promptly. Put that into perspective now; ETH has since reach a new ATH since then and hasn't returned to that "bottom" after those moves.