Wall Street's main indexes were set for a slightly higher open on Wednesday as the Federal Reserve was widely expected to deliver its first interest rate cut in more than four years, with most investors betting on a 50-basis point reduction.

Let's get the basics out of the way: the Fed will announce its latest interest-rate decision at 2 p.m. Eastern, alongside the latest summary of economic projections (i.e., the dot plot). That will be followed by a press conference with Fed Chair Jerome Powell at 2:30 p.m.