"In light of the continued solid performance of the labor market and our outlook for economic activity and inflation, I believe the case for an increase in the federal-funds rate has strengthened in recent months," Yellen said in Jackson Hole, Wyoming. Meanwhile, bullish traders pointed to economic uncertainty and negative interest rates around the world as further support for the precious metal. "Fischer wants to make September still on the table," Mark Kepner, managing director and equity trader at Themis Trading LLC, told Bloomberg.