SG Money Tree: Sometimes stocks go down for no real reason

Been trading Sino Grandness and Yuuzoo recently. These stocks went down for no real reason at all. Other than some news. I bought SinoG at 50 cents, and it dropped all the way to 23 cents. Seeing no big change to the fundamentals, I averaged all the way down too. These 2 stocks seem to have a lot of speculators involved. If they are willing to sell down all the way, this means they didn't buy the stock after doing due diligence. Either that, or there's some bad insider info which I don't know about. Well, we'll wait and see. Assuming the fundamentals are sound, there's a good margin of safety in the price I bought.

Look at NeraTel, though. Even after announcing news that seems to be bad on the surface, it didn't drop much. It mainly dropped because of the ex-dividend. Looks like their investors have more confidence. (Or... maybe it didn't drop yet... Hoping it drops so I can buy it.)