President Trump’s trade policies will make imports more expensive and calculating and paying the tariffs more complicated.

Executives at the largest retailer in the United States acknowledged the new environment, but told investors that they were confident in the company’s strategy.

The iPhone maker spent years trying to move production of some products out of China to avoid tariffs. But now that may not matter.

The electric car company led by Elon Musk builds all the cars it sells in the United States in California and Texas, shielding it from tariffs that could devastate competitors.

The cost of steel pipe used to line oil and gas wells rose after President Trump said he would impose tariffs on steel and aluminum imports.

Xiaomi, which produces smartphones and consumer electronics, delivered 135,000 E.V.s last year after tapping China’s robust manufacturing supply chain.