Swing producer

Wikipedia: “Swing producer is a supplier or a close oligopolistic group of suppliers of any commodity, controlling its global deposits and possessing large spare production capacity. A swing producer is able to increase or decrease commodity supply at minimal additional internal cost, and thus able to influence prices and balance the markets, providing downside protection in the short to middle term. Examples of swing producers include Saudi Arabia[1] in oil, Russia in potash fertilizers,[2] and, historically, the De Beers Company in diamonds.”