U.S. stocks were mixed Tuesday amid a steep decline in oil prices, which plunged more than 4% to roughly $45 a barrel for West Texas Intermediate. Hopes of production cuts were fading at this week's meeting of the Organization of the Petroleum Exporting Countries in Vienna. Saudi Arabia said that supply and demand in the oil market will balance out even without a deal. A decision is expected Wednesday. The second estimate of third-quarter GDP was revised higher to 3.2% growth on an annualized basis, beating estimates of 3.1% and a few notches higher than the initial estimate of 2.9%. Shares of Tiffany (TIF - Get Report) rose after third-quarter profit of 76 cents a share topped estimates of 70 cents. Same-store sales fell 2%, but analysts had expected a 4.1% decline. UnitedHealth (UNH - Get Report) shares were in focus after the company said it expects adjusted earnings between $9.30 and $9.60 a share for fiscal 2017, topping estimates of $7.51. TheStreet's Scott Gamm reports from Wall Street.