Shares of Apple Inc. and UnitedHealth are retreating Friday afternoon, sending the Dow Jones Industrial Average into negative territory. Shares of Apple Inc. and UnitedHealth are contributing to the index’s intraday decline, as the Dow was most recently trading 218 points lower (-0.6%). Apple Inc.’s shares have fallen $5.05, or 3.3%, while those of UnitedHealth have fallen $7.90 (1.9%), combining for an approximately 85-point drag on the Dow. Walgreens Boots Boeing and Salesforce.com Inc. are also contributing significantly to the decline. A $1 move in any of the benchmark’s 30 components results in a 6.58-point swing.