He may or may not purchase it back. As per reliable sources, he received $292 million from the sale. I don't know how the IPO/direct listing sales are taxed, but taking a conservative rate of 40%, he will be left with some $175 million in hand. Why should he spend that money to purchased the stocks he just sold? That makes no sense, as he has already paid a 40% tax. My guess is that Brian Armstrong will continue to sell a part of his stock holdings at regular intervals.