Shares of Amgen and UnitedHealth are trading lower Tuesday afternoon, though the Dow Jones Industrial Average is trading roughly flat. The Dow DJIA, +0.30% was most recently trading 20 points, or 0.1%, lower, as shares of Amgen AMGN, -1.63% and UnitedHealth UNH, -1.40% account for -26% of the index’s intraday movement. Amgen’s shares are down $4.62 (1.7%) while those of UnitedHealth have dropped $9.04, or 1.7%, combining for an approximately 90-point drag on the Dow. A $1 move in any of the benchmark’s 30 components equates to a 6.59-point swing.