Good factors are those unexpected or those still exerting positive effects, all these factors you mentioned are known in this universe,,, kekeke,,,,
Only basic factors known to all could have positive effect, that's the key to value-investing,,,,
Besides, the 2nd mortgage problem is not gone, but currently US employment and housing market condition can give it a break, anyone who live in US will know that the realty bubble is very critical recently, very easy to be burst,,,
Big player buying stocks are slightly positive, but not an excuse for frying such big elephant up,,,
Bank merger wave is positive to those involved, usually the "child", not the mother, HSBC has growing problem to further acquire Chinese banking stocks [it probably can't maintain the 19.9% holding of Bank of Communications after launching a-share], search relevant news in yahoo to enrich your understanding of the situation la,,,,
With 13 p/e and a coming few percent growth, HSBC is still cheap, good for long-term investment,,, if I'm retiring tomorrow, I'll definitively collect +20 more lots HSBC in my portfolio for stable dividend, but too bad I still have to work,,,