Wall Street is sliding toward losses in premarket trading after Walmart, the nation’s biggest retailer and a bellwether for the health of the American consumer, gave a disappointing 2025 forecast.

However, the S&P 500 ( ^GSPC 0.24%) is generally considered the best barometer for the overall U.S. stock market due to its scope and diversity. Read on to see the S&P 500's average return over the last decade, and to learn what Wall Street expects in the future.

Microsoft was the strongest force pushing the S&P 500 upward. It rose 1.3% after saying it had developed what it calls the world’s first “quantum processing unit,” which cou