Rising interest rates tend to drive up U.S. Treasury yields which in turn boost the U.S. Dollar while pressuring foreign demand for dollar-denominated commodities like gold. Yellen's comments combined with a rise in U.S. Treasury yields and reduced fears over North Korea helped make the U.S. Dollar a more attractive investment. She essentially said that the Fed may have overstated the labor market's strength and rate of inflation, indicating future monetary policy will be more accommodative than previously thought.