Shares of Intel and Boeing are trading lower Monday afternoon, sending the Dow Jones Industrial Average into negative territory. Shares of Intel INTC, -1.73% and Boeing BA, -1.62% have contributed to the blue-chip gauge’s intraday decline, as the Dow DJIA, -0.36% was most recently trading 109 points (0.3%) lower. Intel’s shares are down $1.25, or 1.9%, while those of Boeing are off $4.62, or 1.9%, combining for a roughly 39-point drag on the Dow. Also contributing significantly to the decline are Salesforce.com Inc. CRM, -0.61%, Nike NKE, -1.30%, and American Express AXP, -0.97%. A $1 move in any of the index’s 30 components results in a 6.58-point swing.