Shares of UnitedHealth and Salesforce are trading lower Wednesday morning, sending the Dow Jones Industrial Average into negative territory. Shares of UnitedHealth UNH and Salesforce CRM have contributed to the blue-chip gauge’s intraday decline, as the Dow DJIA was most recently trading 139 points lower (-0.4%). UnitedHealth’s shares are down $39.06, or 8.0%, while those of Salesforce are down $0.87 (0.4%), combining for an approximately 263-point drag on the Dow. Also contributing significantly to the decline are Merck MRK, McDonald’s MCD, and Microsoft MSFT. A $1 move in any of the Dow’s 30 components results in a…