Federal Reserve Chair Jerome Powell is set to give what could be his most consequential speech yet — just a few days after one of his colleagues was threatened with prosecution for alleged mortgage fraud.

Fed Chair Powell sparked a big rally as he signaled the central bank could cut rates in September in his remarks at the Jackson Hole policy symposium.

U.S. stocks were rallying midday Friday on Federal Reserve Chair Jerome Powell’s Jackson Hole speech, as traders seemed more optimistic that the Fed may cut interest rates next month. The Dow Jones Industrial Average was up almost 907 points,