Is the last rising of Bitcoin a sign of starting closed trading structures?

Example:

The daily volantlity is about 5.000 Bitcoins.

Some people build up a group, which own´s 10.000 Bitcoins.

Through that difference of Bitcoins they can make the price fall or rise, like they want...by selling or buying among themselves.
->The Bitcoins stay in a closed trading Structure.

Is that just a silly thought or theoretical possible?


Thx