U.S. equities were mixed at midday as the markets weighed the potential impact of President-elect Donald Trump's plan to slap steeper tariffs on imports from China, and new ones on Canadian and Mexican products. The Dow Jones Industrial Average fell, while the S&P 500 and Nasdaq rose.

Amgen (AMGN) was the worst-performing stock in the Dow and S&P 500 after the biotech reported results from a study of its experimental weight-loss drug that came in below expectations.

Shares of Best Buy (BBY) tumbled when the electronics retailer missed profit and revenue estimates and slashed its outlook, which it blamed on macroeconomic worries, customers waiting for deals, and the run-up to the presidential election.

Constellation Brands (STZ) shares fell as the possible tariffs on Mexico could raise the price of its Modelo beer, the top-selling brand in the U.S. 

J.M. Smucker (SJM) shares jumped when the maker of jellies and other food products raised its guidance on higher demand for its packaged and frozen foods.

Shares of Eli Lilly (LLY) and American depositary receipts (ADRs) of Novo Nordisk (NVO) advanced when the White House proposed new rules for Medicare and Medicaid that would expand coverage for weight-loss treatments. 

Walmart (WMT) shares gained following a report that said customers of rival Target (TGT) were unhappy with the retailer's long lines, lack of inventory, and locked-up products. Target shares slid.

Oil and gold futures climbed. The yield on the 10-year Treasury note was little changed. The U.S. dollar gained against the euro and pound, but lost ground to the yen. Bitcoin rose 1% to above $94,000.