Several firms have issued commodity-indexed bonds with exposure to prices of commodities such as oil, gold, or silver. In a way, this technique closely resembles the tactic by which a US firm hedges its overseas risk by issuing bonds denominated in a foreign currency. An oil-drilling firm’s cash flows are sensitive to the price of oil, as are the cash flows of gold-mining or silver-mining firms to the prices of those commodities. By making coupon interest and/or principal amounts vary along with the commodity price; these firms can reduce their risk of bankruptcy. Falling commodity prices reduce such a firm’s cash flows, so its debt service requirements decline, as well.