Those "huge buys" (aka huge sells) are generally prearranged deals between big players that will take place at the closing price. I would not read too much into it. IMO.
That being said I am very bullish on all PE.
I am going by the chart - hourly (in this case, the last hour of trading Friday) provided by Ameritrade. It looks like one trade right at close for 662,850 shares @ $31.49-$31.69. The price spike bears this out. I don't wholeheartedly advocate basing any investment decision one source. I looked at the Yahoo charts, and they don't show what my Ameritrade chart does.
If you go to the 1 day chart under Basic Technical Analysis on this site, it clearly shows a dramatic jump in price & volume in the last few minutes of trading. There are several trades at or approaching 50,000 shares.
Also, a large buy of Black Rock (BLK) stock came in at end-of-day. No uptick, but still a large ($13 million) purchase. Black Rock is also in capital markets - higher valuation, at $299 a share, and large market-cap ($55 Billion).
Looks like a similar buy, without as much upside on BX (Blackstone Group) at end-of-day. BX is a much larger Co. (at $34 billion market cap), but I think business model similar to APO. Buy-in to BX was 342,000 shares - about a $10 million buy.