Stocks are starting higher on Wall Street Wednesday, potentially setting up the S&P 500 to break a four-day losing streak. The benchmark index was up 0.3% in the early going, led by gains in banks and industrial companies. Facebook was leading communications companies lower with a 2.7% loss after the social media company’s oversight board says it will review an internal system that exempted high-profile users from some or all of its rules. FedEx fell after reporting sharply higher costs even as demand for shipping increased. Investors will be watching the Federal Reserve’s announcement after its latest policy meeting later in the day.