I’m sure anybody that has the means already knows that this would depress prices. So they withhold it, and use it as leverage and collateral..............
I doubt you are correct. Instead they WILL be stupid and first dump their resources on the markets to depress prices, to put competitors on financial skids, so that many of its competitors go under, which the new $Trillionaire will scoop up, until they have a near monopoly and command what prices they want to.
Ahhh, but all monopolies contain the seeds of their own destruction, generating a necessary search for and creation of alternatives to the point that the monopoly has caused the production of true competitors to itself. By then market prices of the precious metals of the monopolist will be reduced back to and below their pre-monopoly prices, eating away at the monopolists wealth at the same time.