That is a sum of missed trades that did not post during the regular session. It's below the close because the stock was on an uptrend from about 11:30 on.
Someone is selling out of the money puts like crazy. Buyer is forced to delta hedge by shorting the stock, to remain neutral. Remember, there is a huge short position, and it's the last day of the month.
Shorts are selling out of the money puts like crazy, forcing the specialist to short to remain delta neutral. It only works for 3 days. They are out of stock to short, so this is the only course they have available. There is a good writeup on SHU.
It had a lot more to do with the 7,000+ calls open at $90, than anything else. That would have represented a $1,050,000 hit for the seller, had they allowed the stock to close at $91.50, So they shorted like crazy in that range, started the drop a little before 2, and covered in the last half hour, while keeping the price withing striking distance of $90.
This is options expiration, nothing more. There are a ton of calls sitting at $90. Seller is working hard to get them to expire worthless. I just bought more.
Gerald - you are either extraordinarily naïve. or a basher known as a snake. You pretend to be long, and at the same time sow fear, uncertainty and dread. Either way, your posts are useless at best.