President Trump has defended his decision to introduce tariffs on goods from other countries by arguing that it will lead companies to shift production to the United States, bringing back jobs.

For German companies, which have been producing their goods in the United States since the late 1800s, such arguments ring hollow. Thousands of German companies already have factories in the United States, accounting for 12 percent of the country’s foreign investments.

Automakers like BMW and Mercedes-Benz have long had plants in the United States. In 2023, the candy maker Haribo opened its first U.S. plant in Wisconsin, after decades of importing its gummy bears.

Many German companies are now calling that strategy into question. Recent surveys indicate that German manufacturers are pulling back from investing in the United States, and those that already have a footprint there are more gloomy about their futures.

The German Chamber of Commerce and Industry regularly polls the 6,000 German companies with U.S. factories to gauge their outlook on the economy. For years, those companies held an “above average” view, said Volker Treier, the head of foreign trade at the chamber. But since Mr. Trump announced the initial round of tariffs on April 2, sentiment has dropped.

“They have fallen against the trend,” Mr. Treier said. “Because tariffs are poison.”