Ann: General Security Agreement, page-161

Many reasons why would they would need to close their shorts, if the POG rises or is manipulated higher by fast frenzied buying of gold futures contracts sending the price surging and triggering stop losses and subsequently a short squeeze in which their will all of a sudden be huge buying pressure. These are naked shorts, they don't own the underlying contract, to close out their position they would need to acquire the contract at current market prices and if the prices are higher than what they shorted, they'd be incurring losses. There is nothing stopping the bullion banks from continuing this cycle, however, it is becoming less and less effective because of the actual strong physical demand. (DYOR on the increased physical deliveries from 2020). You eventually can't deliver what you don't have...