There's no easy way to know who has transferred to whom unless the transferrer or transferee tells us about it and that's the beauty of bitcoin where the owner of the money controls it. Just imagine this kind of transaction happens in real world through a banking channel. The bank and investigation agencies will go nuts about it. But with bitcoin, there's no easy way to know it!

Secondly, it is highly possible that this transfer is a part of some institutional investment. Corporates are showing great interest about bitcoin since last few months and that's what is making this year's bull run quite different than of 2017. But US government will soon step into it and start probing the companies who had bought large quantities of bitcoin in last few months and publicly acknowledged it!