Nov 3 (Reuters) - U.S. stock indexes opened flat on Wednesday as investors refrained from making big bets ahead of the conclusion of a Federal Reserve meeting, where policymakers are widely expected to signal the withdrawal of its pandemic-era support. The Dow Jones Industrial Average rose 6.46 points, or 0.02%, at the open to 36,059.09. The S&P 500 opened flat at 4,630.65, while the Nasdaq Composite gained 8.91 points, or 0.06%, to 15,658.52 at the opening bell. (Reporting by Devik Jain in Bengaluru; Editing by Maju Samuel)