For me, this is a such a huge amount worth of Bitcoin to be moved in another address in only 15 minutes. However, it's still a mystery whatever the reason is.
These whales are just fortunate enough to accumulate Bitcoin during the early times. Until now, I still regretted in doubting about investing in Bitcoin years ago.
Correct me if I'm wrong, but these whales know what they are doing. They are here for the long-term since they have enough BTCs in their arsenal, especially the next year's halving. However, I would not really count on halving's guarantee of BTC's price pump.
It's likely not a whale but an exchange consolidating it's accounts. If they have a lot of dust they will move it to consolidate it into fewer addresses.
Most bitcoins are held at the major exchanges rather than in whales wallets.
It was an exchange, it was Bittrex. I did make me think though, since all of these wallets were hot for a period. I could only imagine what could happen to the market if there was a hack that big, it would be devastating.