I've purchased numerous time PMDP along with other .000's and my initial orders are usually start from 30mil and every execution has been filled with 9mil blocks.
What we saw today with those 9mil blocks is one entity purchasing a big block. I didn't look into details, but it's very obvious if u pay attention closely you can easily say how many shares was purchased/sold by that one order. Say if the blocks go 3X9 mil then 3mil in a same sec, usually that's an 30 mil order being filled (mo matter it's a buy or sell, and of course the bid/ask have to support the volume too).