BERLIN (Reuters) - Porsche has shipped added inventory to the United States to get ahead of tariffs and kept prices constant for orders made in March, executives told analysts and investors in a call on Wednesday, according to a note by Bernstein Research.

The luxury carmaker expected an operating margin below its annual guidance of 10-12%, the note said, adding that this margin also did not account for the impact of 25% tariffs on auto imports to the U.S., which were not included in the 90-day pause announced on Wednesday.

Executives did not provide further detail on the longer-term strategy to deal with the tariffs, according to the note.

Porsche did not immediately respond to a request for comment. The investor call was held before a closed period on company information before annual results scheduled for April 29.

Among the German automakers, Porsche and Volkswagen's Audi - two brands with no U.S. production - have both said recently they would assess the option of price increases to mitigate tariff risks.

In the meantime, Audi is holding cars in U.S. ports, while Mercedes-Benz stocked up its inventory in the country before tariffs came into force.