If you look at the wall thread, somebody found his wallet and he has been accumulating coins from 2012-2013. He sold some every few months to take profit and I guess he got out at $300.
Of course he was, 99% of big holders are early adopters. Imagine you had the luck of your life and managed to get a shit ton of BTC for a small amount, it hits 1000, you get greedy, "oh it will go to 2000 easily, let's just wait and become even richier". It starts going down slowly. "Oh it will go back up". And you keep this mentality for ages, until you are PANICKING and sell the entire stack at market price (300 or whatever). This guy is far from intelligent. This guy is just another lucky guy, just like 99% of big btc holders, that guy scared at the possibility of Bitcoin crashing even harder in the next month. Guy got the fuck out, that's that. Now he's enjoying his money, but not without the bitter sensation of maybe Bitcoin starting to recover as you just sold. This was justa big hand getting shaked.