The last trading days and first trading days of month/ quarter have some unique characteristics in my opinion. Tomorrow is the first trading day of October/4th quarter and today was the last trading day for September/ 3rd quarter. I noticed that sometimes the last and first trading days of the month will have larger than normal moves. my guess is that: 1.large funds are positioning themselves or "squaring off books" for accounting purposes. 2.Longer term traders have the full picture of the monthly chart Either way, always good to do some homework, go back in your charts and see if you are able to notice any patterns etc.