Federal Reserve Chair Jerome Powell just gave Wall Street—and Main Street— a reason to celebrate. In a closely watched speech at the Fed's annual Jackson Hole conference, Powell sent a clear signal that the central bank is preparing to shift its stance on interest rates as early as next month.

Wall Street cheered remarks from Federal Reserve Chair Jerome Powell in Jackson Hole opening the door to a rate cut in September.

World shares are mixed after Wall Street fell to a fifth straight loss, and as traders look for cues about U.S. monetary policy from a meeting of central bankers in Jackson Hole, Wyoming