If you don't mind me playing the 'Devils Advocate' for one...

If you don't mind me playing the 'Devils Advocate' for one moment - there is another more probable answer. Its called 'pass the parcel'.

With some decent rumours /news a player or players start trading shares amongst themselves and from the market to drive the price up (tip - you need a decent parcel of low cost shares to start).

Then, when all the activity pulls the traders / daytraders in they start picking up some of the volume for you but are very short term holders (churn) and the insiders who started it all start unloading stock into the mellee.

Its the ultimate recycling program really.

Then, when the real player/s in the stock have finished and no-one is left to play because the party is over, the stock quietly slides back down to where it started.

The players can then get set again if they wish.

"At the beginning of a resources boom the mine owners have all the paper and the investors have all the money - at the end of the resources boom the mine owners have all the money and the investors have all the paper."

Cheers,