Trump's first address to a joint session of Congress on Tuesday evening is being closely watched by investors for clues on how he planned to carry out his agenda of boosting economic growth.
In a meeting with state governors, Trump said his administration would be "moving quickly" on regulatory reforms and that his tax plan would be released after a proposal on Obamacare.
"If we have a market that is willing to accept a roadmap that says we are going to repeal and replace Affordable Care Act and then have some form of tax reform by the August recess, I think the market will continue to be supportive," said Art Hogan, chief market strategist at Wunderlich Equity Capital Markets in New York.
Trump's promise a few weeks ago of a "phenomenal" tax announcement helped rekindle a post-election rally, driving the main U.S. markets to record highs.
But with details scant on how he planned to implement his agenda, investors have turned wary and the markets have traded range-bound.
At 12:27 p.m. ET, the Dow <.DJI> was down 7.78 points, or 0.04 percent, at 20,813.98, the S&P 500 <.SPX> was down 0.42 points, or 0.01 percent, at 2,366.92 and the Nasdaq Composite <.IXIC> was down 0.21 points, or flat, at 5,845.10.
Six of the 11 major S&P 500 sectors were higher, with energy <.SPNY> rising on higher oil prices.
Utilities <.SPLRCU>, consumer staples <.SPLRCS> and telecom services <.SPLRCL> - defensive plays that were last week's top performers - were the big losers on Monday.
Among stocks, electric carmaker Tesla (>> Tesla Inc) fell 4.4 percent to $245.57 after Goldman Sachs downgraded the company's stock to "sell" from "neutral" and lowered its price target.
Time Warner (>> Time Warner Inc) hit a near 16-year high of $98.31 following a report by the Wall Street Journal that the Federal Communications Commission chairman said he does not expect the agency to review AT&T's (>> AT&T Inc.) deal to buy Time Warner.
AT&T slipped 1.3 percent and was the top drag on the S&P telecom index.
Shares of U.S. defense companies - Boeing (>> Boeing Co), Raytheon (>> Raytheon Company), General Dynamics (>> General Dynamics Corporation) and Lockheed Martin (>> Lockheed Martin Corporation) - rose after Trump said he would seek to boost Pentagon spending by $54 billion in his first budget proposal.
La Jolla Pharmaceutical (>> La Jolla Pharmaceutical Company) surged nearly 77 percent to $35.11 following the success of its lead experimental drug in a late-stage study.
Advancing issues outnumbered decliners on the NYSE by 1,695 to 1,146. On the Nasdaq, 1,560 issues rose and 1,191 fell.
The S&P 500 index showed 51 new 52-week highs and one new low, while the Nasdaq recorded 100 new highs and 35 new lows.
(Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Sriraj Kalluvila)
By Yashaswini Swamynathan