U.S. equities were higher at midday Tuesday after the long weekend as the market anticipated tariffs threatened by new President Donald Trump won't be as severe as initially thought. The Dow Jones Industrial Average, S&P 500, and Nasdaq were higher.

Moderna (MRNA) shares jumped after the biotech firm said that it was getting a $590 million award from the U.S. government to develop a vaccine that can be used to fight bird flu.

Shares of 3M (MMM) rose when the maker of Post-it notes and Scotch tape posted better-than-expected results as a wide range of its products experienced increased demand.

Ulta Beauty (ULTA) shares climbed when Morgan Stanley upgraded the stock and boosted its price target, arguing that the beauty products maker will continue to grow and gain market share. 

Among decliners Tuesday, Walgreens Boots Alliance (WBA) was the worst-performing stock in the S&P 500 after the Justice Department sued the biggest U.S. pharmacy chain, accusing it of filling "millions" of unlawful prescriptions for dangerous opioids and other addictive drugs.

Apple (AAPL) shares fell on a downgrade from Jefferies, which pointed to a soft artificial intelligence (AI) outlook for the company and the likelihood the iPhone maker's fiscal first-quarter revenue will miss estimates later this month.

Shares of Tesla (TSLA) and rival electric vehicle (EV) makers declined when Trump signed an executive order reversing a government mandate that half of all vehicles made in the country had to be electric by 2030. Trump also suggested tax incentives for EV buyers be eliminated.

Oil futures slid. Gold prices gained. The yield on the 10-year Treasury note dropped. The U.S. dollar was little changed against the euro, pound, and yen. Most major cryptocurrencies traded higher.