US equity indexes fell as an expedited implementation of copper tariffs increased uncertainty over impending import levies, and an unexpected increase in durable goods orders helped lift government bond yields.

The Nasdaq Composite dropped 2.2% to 17,872.9, with the S&P 500 down 1.3% to 5,703.7 and the Dow Jones Industrial Average 0.5% lower at 42,384.9 after midday Wednesday. Technology, consumer discretionary, and communication services led decliners intraday. Consumer staples and energy were among the top gainers.

Nvidia (NVDA) and Tesla (TSLA) led the Magnificent-7 stocks lower, giving up some of their gains from this week. According to a DA Davidson note, investors are turning cautious as they await clarity on tariffs that the Trump administration will announce on April 2.

US tariff developments aren't helping risk appetite, Derek Holt, head of capital market economics at Scotiabank, said in a note, referring to an "expedited move to impose a 25% tariff on copper imports into the US that could be implemented within weeks and hence on a much shorter timeline than previously understood."

US copper prices have surged almost 30% so far this year, Holt said in the note. "Expect pass through into US building and other costs, including electronic components, and substitution effects toward other options where possible like any home being built that doesn't already use alternatives to copper piping shifting away from copper."

On Tuesday, President Donald Trump reportedly told Newsmax that he "doesn't want to have too many exceptions" to the import levies he plans to announce next week.

Meanwhile, in economic news, new orders for US durable goods rose by 0.9% in February following a 3.3% jump in the previous month, compared with expectations for a 1% drop in a survey compiled by Bloomberg. Excluding a 1.5% gain in transportation orders, new orders would have risen 0.7% in February after a 0.1% increase in January. Expectations were for a 0.2% gain.

Most US Treasury yields rose intraday, with the 10-year yield up 3.4 basis points to 4.34% and the two-year rate two basis points higher at 4.00%.

In company news, Dollar Tree (DLTR) agreed to sell the Family Dollar business to investment management firms Brigade Capital Management and Macellum Capital Management in a deal worth roughly $1.01 billion. Its shares climbed 8.1% intraday, the top gainer on the S&P 500.

Cintas (CTAS) reported fiscal Q3 earnings and sales on Wednesday, beating the average analyst estimates compiled by FactSet. The company also raised its fiscal 2025 earnings guidance. Its shares jumped 6.5% intraday, among the top performers on the S&P 500 and the Nasdaq.

West Texas Intermediate crude oil futures jumped 1% to $69.71 a barrel.

US commercial crude oil stocks, excluding inventories in the Strategic Petroleum Reserve, fell by 3.3 million barrels in the week that ended March 21, after a 1.7-million-barrel gain in the previous week. The print compared with the 2-million-barrel increase expected in a survey compiled by Bloomberg.

Gold futures slipped 0.1% to $3,023.11; its silver counterpart rose 0.2% to $34.26.