There is lot of FUD about this, people claiming that Whale number 3 dumping their BTC. Some of them even say it was Saylor's wallet and that he dumped.
This is just FUD. Let's see:
First thing, the Bitcoins were not dumped, those were just moved to a new wallet through Coinbase:
So the owner of 1P5 just moved the funds to 1LQ sending them first to a Coinbase wallet. You can verify that the balance in BTC on 1LQ is almost the same that 1P5 had.
Second thing, about Saylor:
This wallets (1P5 or 1LQ) are not Saylor's wallets. There is ZERO evidence or proof about that. The most convincing explanation I found about this wallet is this one: