I am unworried but congrats to the holders as he has made good fortunes out of the patient holding for the period of time. That is if it was not hackers than invaded the wallet since it is still around the non custodial but on the positive reaction, the owners have been investing based on planes. Probably to diversify if he had realized a specific value within his expectations. That could be why the transaction was not sent to the exchange. And we should not have to expect the market reacting to the action since the funds is still in the same blockchain.
It is so much Bitcoin, that just leaving it there and not touching it five years in a row requires a lot of patience, and it seems that now the whale is not only willing to cash out, but is organizing a more strategic move. Transporting it to a SegWit wallet means they are security conscious or maybe consolidation or diversification over the long term. That it is yet to list in an exchange implies that they are not in a hurry to sell and thus the market is yet to be affected. In a way it reminds us that long-termers can exert their pressure on the ecosystem without triggering a panic and it can be really worth it to be patient in crypto.