April 29 (Reuters) - Wall Street's main indexes were mixed at the open on Wednesday as investors treaded carefully ahead of several Big Tech earnings reports and a Federal Reserve meeting expected to be the last for Jerome Powell as its Chair.

The Dow Jones Industrial Average rose 21.8 points, or 0.04%, at the open to 49,163.78. The S&P 500 fell 7.2 points, or 0.10%, at the open to 7,131.61​, while the Nasdaq Composite dropped 57.3 points, or 0.23%, to 24,606.527.

(Reporting by Niket Nishant and Utkarsh Hathi in Bengaluru; Editing by Devika Syamnath and Arun Koyyur)