September 29th, 2016, 2:55 pm
I guess I should rephrase to be more precise: SPX index closed on 9/29/08 at 1106.42. This means that people left limit-on-close sell orders on the component stocks at levels collectively led to the SPX being at 1106.42. The puzzling thing is that at 15 minutes before close (when they could still pull their LOC orders), the SPX index was trading at1130+ (see below). In order words, some of the component stocks at that time were trading at levels much higher than some of the limit prices of the standing LOC orders on such component stocks. But why wouldn't these people just pull the LOC and hit the bids on such component stocks? Was the market really that thin that one was willing to give up 24 points to trade size? (Or people thought they could get filled in the closing auctions at levels much better than their limit prices given the one-price Dutch auction nature of the closes?)
(Of course, SPX intra-day prints for the first 5 minutes or so, including opne, are meaningless. One should use Emini or SOQ instead.)
SPX intra-day trades (chicago times)
09/29/2008,14:44:36,1134.31
09/29/2008,14:44:51,1134.14
09/29/2008,14:45:06,1133.99
09/29/2008,14:45:21,1133.87
09/29/2008,14:45:36,1132.86
09/29/2008,14:45:51,1131.1
09/29/2008,14:46:06,1130.66
09/29/2008,14:46:21,1131.48
09/29/2008,14:46:36,1131.83
09/29/2008,14:46:51,1132.12
09/29/2008,14:47:06,1130.78
09/29/2008,14:47:21,1130.26
09/29/2008,14:47:36,1129.98
09/29/2008,14:47:51,1128.49
09/29/2008,14:48:06,1128.05
09/29/2008,14:48:21,1128.21
09/29/2008,14:48:36,1128.6
09/29/2008,14:48:51,1128.8