Dec 18 (Reuters) - Wall Street's three main indexes opened at record highs on Monday as the long-awaited tax overhaul plan looked set for legislation and a flurry of year-end corporate dealmaking that has topped $11 billion so far buoyed optimism.
The Dow Jones Industrial Average rose 134.06 points, or 0.54 percent, to 24,785.8. The S&P 500 gained 13.17 points, or 0.492187 percent, to 2,688.98. The Nasdaq Composite added 43.83 points, or 0.63 percent, to 6,980.41. (Reporting by Sruthi Shankar in Bengaluru; Editing by Savio D'Souza)