Shares of Boeing and American Express are posting losses Thursday morning, sending the Dow Jones Industrial Average into negative territory. Shares of Boeing BA, -6.64% and American Express AXP, -5.76% are contributing to the index’s intraday decline, as the Dow DJIA, -1.78% was most recently trading 240 points (0.8%) lower. Boeing’s shares have dropped $4.73 (3.7%) while those of American Express are down $4.82, or 3.0%, combining for an approximately 63-point drag on the Dow. Apple Inc. AAPL, -4.95%, Walt Disney DIS, -2.80%, and Visa V, -3.09% are also contributing significantly to the decline. A $1 move in any one of the 30 components of the Dow results in a 6.59-point swing.