NorthWest Biotherapeutics Inc (NWBO)

[hankmanhub]

They took down the price many time before & after the release of good pr/ presentation they can do it again on MHRA approval.

I am not sure I agree with that. They did it when there was no approval and could at least put forward the idea it might not (or won't) happen. But once the approval is done and history they will find it MUCH more expensive to short and drive down the share price. Maybe if they are willing to throw A LOT OF CASH into the shorting enterprise they might bring the share price down somewhat. At some point they will not want (or be able) to throw sufficient cash at it to keep up the shorting as the market buys up all the bargains they are giving away.
Another key point here is how long they can hold the share price down. Sure, they might manage a bear run for a few hours or even a few days, but to sustain the lower price over a long time (with approvals in hand) will be very expensive and probably not a path they will want to take. It's something like the uncertainty principle in physics. You can get free energy but only for a very very short time before you need to pay it back. The more free energy you took, the shorter the time you can keep it.