US stocks were mixed on Tuesday as Federal Reserve policymakers kicked off a two-day interest rate meeting and investors braced for quarterly scorecards from Apple and Twitter.

The Dow Jones industrial average dipped 0.1 percent to end at 18,473.75 and the S&P 500 edged up 0.03 percent to 2,169.18 after spending much of the day at a loss. The Nasdaq Composite added 0.24 percent to 5,110.05.