why was the dow down?

I can't find any reason for why the Dow went down yesterday. Two pieces of economic news were better than expected (i.e. pending home sales and ISM manufacturing index). One piece of economic news was worse than expected (construction spending but this is less important than the other two pieces of data). Even Shanghai and the Hang Seng gave a green lead to the Dow yesterday.

The only two things which could explain the sell off:

1. It is the month of September and its reputation as a bad month for stocks precedes itself. So traders/investors sold off in advance. Naaah! It can't be that simple.

2. Major US banks are paying back TARP money or other forms of assistance provided by Uncle Sam e.g. Wells Fargo, Bank of America, etc. This would suggest they would need to raise more capital to repay the government. As a result traders/investors could be taking money out of other stocks and keeping it ready for capital raisings.

I think 2. is the more likely reason for the sell off. If you agree, please thumb me.