Here is s&p500 on sun night when it's illiquid, someone had to/tried to dump a bunch at once.

This is what happens when you try to sell all at once in an illiquid market

Word to the wise, don't have a "fat finger" in an illiquid mkt.

http://www.zerohedge.com/news/2013-12-16/visualizing-overnight-stock-index-futures-fat-finger-rout