Merck lifts Dow; S&P, Nasdaq flat ahead of Trump speech

Healthcare stocks boost the Dow early on Wednesday, while the S&P 500 and the Nasdaq were flat ahead of Donald Trump's first formal news conference, where he is expected to give more insight into his plans to boost economic growth. Trump's election in November sparked a record-setting rally. The dollar, which has also basked in Trump's victory, rose to 102.53.