Stocks were mixed Wednesday, with each of the three major indexes trading close to the flat line as investors digested an onslaught of corporate earnings results and looked ahead to a monetary policy decision from the Federal Reserve.

The S&P 500 ticked higher, after the index ended just short of a record high during the regular trading day on Tuesday. Shares of Alphabet (GOOGL) gained after the company posted first-quarter sales and profit that easily exceeded estimates, fueled by a resurgence in advertising spending among customers. Shares of peer tech giant and Dow component Microsoft (MSFT), however, declined even after earnings topped expectations across virtually all major metrics. Apple (AAPL) and Facebook (FB) are poised to report results after market close on Wednesday.

A monetary policy decision from the Federal Open Market Committee on Wednesday will punctuate what has otherwise been a busy week full of corporate earnings results. Many pundits expect the April FOMC meeting will yield virtually no new developments, with policymakers waiting until more data emerges on the economic recovery to determine the timing for an adjustment to their ultra-accommodative policy.

"We expect no major developments for the Fed’s core policies at the April FOMC meeting. Fedspeak since the March meeting has been consistent in acknowledging improved activity amid accelerating vaccinations, re-opening and fiscal stimulus," Lewis Alexander, U.S. chief economist at Nomura, said in a note Tuesday.