An earlier blog post of mine quoted the 35th director of the US Mint on the idea of a trillion-dollar platinum coin. Said it was legal and doable. But the 38th director, Edmund Moy, has big doubts (via CNBC):
First, it may be legal to mint a platinum bullion coin with a $1 trillion face value, but it’s not legal to pass it off as actually worth $1 trillion if there isn’t $1 trillion of platinum in it. That’s because it’s a bullion coin and not a legal circulating coin. The face value of a bullion coin has no relationship with the metal content because the value is in the metal, whose price fluctuates daily.
Second, for a coin to be worth its face value, it has to be made as a circulating coin.
Here’s how a circulating coin is made. Congress needs agree on the metal content, dimensions, the designs on the heads and tails sides, weight, and other details. Then they have to pass legislation to create a $1 trillion circulating coin. The President needs to sign it. Then the Mint would have to design it get the design approved, procure whatever new materials they need, make the dies, test production, and then make one. Then a bank would have to order one because a business customer needed it to make change. The Fed would pay the Mint face value for the coin. After deducting the cost of the coin, the Mint would return the balance to the Treasury. All this needs to be done before we run out of money. Good luck with that.