The Dow Jones industrial average slipped 42 points, or 0.2 per cent, to 15,986 in midday trading Tuesday.
The Standard & Poor's 500 index was down four points, 0.3 per cent, to 1,803, just below its latest all-time high reached the day before. The Nasdaq composite fell six points, 0.1 per cent, to 4,062.
Banking stocks were mostly higher after investors got some clarity on new banking regulations.
Federal regulators voted to approve the so-called Volcker Rule, which bars banks from betting on the market with their own money.
Goldman Sachs was up $2.48, or 1.5 per cent, to $179.16 while Morgan Stanley was up 36 cents, or 1 per cent, to $30.75.