Buoyed by positive momentum for shares of Caterpillar and Apple Inc., the Dow Jones Industrial Average is rallying Thursday morning. Shares of Caterpillar CAT, +3.77% and Apple Inc. AAPL, +3.75% have contributed about a quarter of the index’s intraday rally, as the Dow DJIA, +1.71% is trading 463 points (1.7%) higher. Caterpillar’s shares are up $5.76 (3.7%) while those of Apple Inc. are up $3.93, or 3.4%, combining for an approximately 64-point boost for the Dow. Microsoft MSFT, +3.32%, Visa V, +2.91%, and Dow Inc. DOW, +2.38% are also contributing significantly to the gain. A $1 move in any of the index’s 30 components equates to a 6.58-point swing.