"The new American president has a style that's different from what we're accustomed to," Joe Kaeser told a news conference ahead of the engineering group's annual shareholder meeting. "It worries us, what we see. But it's a great country."
Siemens employs more than 50,000 people in the United States, its single biggest market, where it makes 21 percent of its total revenue.
"The country has a tradition of openness, freedom, integration," Kaeser said. "It would be a terrible shame if ... one would give this up only because one thinks one would guarantee security."
Kaeser added that he was making plans for how to deal with the new U.S. administration but declined to elaborate beyond saying that Siemens was talking to state governors.
Siemens raised its earnings forecasts on Tuesday after industrial business profit jumped 26 percent in the fiscal first quarter, lifted by its factory automation unit.
The German trains-to-turbines company said it now expected an industrial profit margin of 11-12 percent for the year to end-September, versus its previous forecast for 10.5-11.5 percent. It made 13 percent in the first quarter.
Siemens also raised its earnings-per-share forecast to 7.20 to 7.70 euros from previously 6.80 to 7.20.