Shares of UnitedHealth and Travelers are trading lower Thursday morning, dragging the Dow Jones Industrial Average into negative territory. Shares of UnitedHealth UNH, -5.27% and Travelers TRV, -1.88% are contributing to the index’s intraday decline, as the Dow DJIA, -0.11% was most recently trading 259 points (0.8%) lower. UnitedHealth’s shares have dropped $18.49, or 3.7%, while those of Travelers have fallen $6.83 (3.7%), combining for a roughly 167-point drag on the Dow. Also contributing significantly to the decline are Honeywell HON, +0.32%, Merck MRK, -3.29%, and Amgen AMGN, +0.05%. A $1 move in any of the Dow’s 30 components results in a 6.59-point swing.