Wall Street rallies on stimulus cheer, trade optimism

China's central bank unveiled a key interest rate reform on Saturday to help steer borrowing costs lower for companies, close on the heels of reports of a potential German economic easing. After the three main Wall Street indexes racked up their third straight weekly loss despite Friday's bounce, investors will look to weigh trade risks and signs of slowing growth against the potential for more action from the U.S. Federal Reserve and others in September. The focus this week will be on Wednesday's release of minutes from the Fed's July policy meeting, when the central bank cut rates for the first time in more than a decade, and Chair Jerome Powell's speech at a central banks meeting in Jackson Hole on Friday.