Co's with small free floats of shares

I have just seen that on a share I own, HET, that the free float of shares, ie those not held by people owning over 3% or more each is, down to 3.7% of which another poster I believe owns 2% which leaves 1.7% of the company available for trading.

This has in HET's case led to a prolonged downturn in the shares and now a rally which despite a pullback on Thurs/Fri has been on a very low volume of shares.

I started this thread with an idea to get a list of those companies which are not only volatile due to the market they trade on, the majority would appear to be on AIM, but that this is multiplied due to the tightly held nature of their shares.

MRM and SRTS are two more thqat spring to mind though not to the same level.

These stocks have the ability to move rapidly and I would be interested to see if anyone has any other stocks with the same characteristsics as I would like to set up a watchlist of stocks of this type.