Economic indicators suggest a slowdown in U.S. economic growth. Click here to read more about how this could impact investor sentiment.

So far, the Federal Reserve has avoided commenting on the increasingly uncertain outlook, but investors are waiting to see whether it changes its projections on Wednesday.

U.S. stock indexes are rising Wednesday after the Federal Reserve kept its main interest rate steady, as was widely expected. The S&P 500 was up 1.7% in afternoon trading, adding to its gains following the Fed's announcement.