Our currency has not been pinned to gold for 40 years (when the Bretton Woods system collapse), but the Federal Reserve still maintains the holdings.
Before the Bretton Woods system collapsed, the US government was required to allow large entities to exchange their USDs for gold. Now, it isn't required to. But the fact that the Federal Reserve holds the gold, and that it is well known that they would use it to support the value of the USD, helps maintain the value of the USD.
Our currency has not been pinned to gold for 40 years (when the Bretton Woods system collapse), but the Federal Reserve still maintains the holdings.
Before the Bretton Woods system collapsed, the US government was required to allow large entities to exchange their USDs for gold. Now, it isn't required to. But the fact that the Federal Reserve holds the gold, and that it is well known that they would use it to support the value of the USD, helps maintain the value of the USD.