US stocks closed mixed Thursday after two straight days of gains, the AP reports. Chemical makers and banks slid while utilities and phone companies gained. Monsanto fell nearly 2% and Dow Chemical fell 1.7%. The chemical sector had gotten a boost earlier in the week on news of a potential sale of Monsanto to Germany's Bayer. Discount retailer Dollar Tree rose 13% after it raised its forecasts for the year. The Dow Jones industrial average slid 23 points, or 0.1%, to 17,828. The Standard and Poor's 500 index was unchanged at 2,090. The Nasdaq composite rose 7 points, or 0.1%, to 4,902. (More Dow Jones stories.)