Most shares in the S&P 500 rose, but renewed tech weakness weighed on the gauge, with Nvidia tumbling 5%.
While the Fed is expected to hold benchmark rates at the highest level in more than two decades, traders will be closely watching for any hints that the start of policy easing is near.
The S&P 500 Index has probably already logged the gains it will see this year, but the benchmark still presents opportunities for investors, says BofA.