Over the past twenty years, the US has turned to from a lender to large debtor vis-à-vis the rest of the world. Still, its income balance has stayed positive as the US earns a higher return on its foreign assets than it pays on its foreign liabilities.
Estimates put the annual benefits to the United States of the dollar’s key currency role at 2 percent of US GDP (Gourinchas and Rey 2007). Key currency status also serves as an insurance policy in case of economic and financial stress.