US trading began mixed on Wednesday amid the continued flurry of corporate earnings, but investors appeared to be waiting for the conclusion of the Federal Reserve's policy meeting later in the day.
"The earnings news has been spectacular, yet the response has been spectacularly lackluster so far," said Briefing.com analyst Patrick J. O'Hare.
Meanwhile, after 100 days in office, President Joe Biden is set to unveil his $1.8 trillion American Families Plan, funded by ending tax cuts and closing loopholes used by the most wealthy, including raising the capital gains tax on those making $1 million a year.
About 30 minutes into the session, the benchmark Dow Jones Industrial Average was down 0.4% 33 853.36.
But the broad-based S&P 500 added 0.2% to Monday's record to sit at 4 195.96, and the tech-rich Nasdaq Composite Index reversed its early loss to rise 0.1% to 14 106.66.
Rising prices have begun to raise concerns about inflation, despite Fed Chair Jerome Powell's assurances any spikes are likely to be temporary.
The central bank has pledged to keep interest rates low until inflation tops 2.0% and stays there, but some economists have begun to worry that its low rates and aggressive bond-buying program will need to be dialed back.
"The intrigue - or hesitancy - is wrapped up in what Mr. Powell will say and whether he makes any inkling of a reference to the Fed starting to discuss when it might consider tapering its asset purchases," O'Hare said.
Among individual stocks, Boeing dropped 3.6% after reporting a loss of $537 million in the first quarter, its sixth quarter in a row in the red.
Google-parent Alphabet jumped 5.6% after reporting following the end of trading on Tuesday that profits leapt to $17.9 billion.
Apple and Facebook, which will report after the close Wednesday, were both showing modest gains.