Wall Street rises as Yellen says case for rate hike stronger

Yellen, speaking before a gathering of global central bankers in Jackson Hole, Wyoming, did not indicate when the Fed would raise rates, but said the central bank thinks future hikes should be "gradual". "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 prepared remarks. Bank of America , JPMorgan , Goldman Sachs' , Ci