Two that come to mind are Coinbase & Circle. I did a quick google search, possibly wrong terms. The information I got was useless. I am sure this has been discussed. If there is a good article/link on this it would be appreciated.
They are big bosses, they have been in the bitcoin industry for a long time or maybe since the beginning of the bitcoin and have invest in bitcoin when the price was really cheap and they hold them and have re-invested them to build good exchanges.