Shares of Boeing and American Express are posting losses Thursday morning, sending the Dow Jones Industrial Average into negative territory. Shares of Boeing BA, -4.83% and American Express AXP, -3.84% are contributing to the index’s intraday decline, as the Dow DJIA, -0.33% 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, -2.69%, Walt Disney DIS, -0.86%, and Visa V, -1.21% 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.