World oil supply disruptions lead to U.S. economic losses. Because oil is fungible in an integrated world oil market, increased oil consumption, whether from domestic or imported sources, increases the economic losses associated with oil supply disruptions. Nevertheless, increased U.S. oil production expands stable supplies and dampens oil price shocks, whereas increased U.S. oil imports boosts the share of world oil supply that comes from unstable producers and exacerbates oil price shocks. Some of the economic losses associated with oil supply disruptions—gross domestic product losses and some transfers abroad—are externalities that can be quantified as oil security premiums. To estimate such premiums for domestic and imported oil, we take into account projected world oil market conditions, probable oil supply disruptions, the market response to oil supply disruptions, and the resulting U.S. economic losses. Our estimates quantify the security externalities associated with increased oil use, which derive from the expected U.S. economic losses resulting from potential disruptions in world oil supply.