U.S. stock index futures were flat to slightly lower on Wednesday as investors braced for a spate of economic data and corporate results to close a turbulent month for financial markets. First-quarter gross domestic product data,

Stock futures were falling early Wednesday after gaining in the previous session as the U.S. trade war started to hit economic data, an ominous sign that the real-world impact of President Donald Trump’s tariffs will soon be felt.

First-quarter gross domestic product data, March's reading of the PCE price index - the Federal Reserve's preferred inflation metric - and ADP employment figures are all due on the day. Caterpillar Inc is among the many companies reporting results before the bell,