The markets were trading narrowly mixed in midday trading Monday with the S&P 500 and Dow Jones Industrial Average moving higher, while the Nasdaq slipped. Biotech was weighing on the Nasdaq as Gilead Sciences fell nearly 2%. The drugmaker was lower on reports it had warned health providers that its leading HEP C drug caused complications when taken with certain heart treatments. The U.S. dollar boosted stocks elsewhere as it continued to fall from 12-year highs against other major currencies. The greenback has been under pressure after the Federal Reserve suggested a slower-than-expected rate hike timeline last week.