Wall Street set to open lower as investors assess data

The Dow and the S&P 500 were on track to post slight gains for the week, but the Nasdaq was poised to close lower in a choppy week that saw China devalue its currency, hitting markets and derailing predictions of a rate hike. Most traders and economists are expecting a September rate hike, but macro concerns have prompted some to argue that the Fed may wait until December to hike interest rates for the first time in nearly a decade.