GENEVA (Reuters) - Swiss watch seller Sacha Davidoff was scrambling on Thursday to understand what new U.S. tariffs on Switzerland announced by President Donald Trump meant for the goods he was due to export from his shop in Geneva this week.

"I made a deal and now we're stuck. We are supposed to ship the watch, but what do we do now? He (the client) won't want to pay 31% more. It doesn't feel real," Davidoff said.

Shares in European luxury companies dropped on Thursday after Trump announced import tariffs, including 31% on goods from Switzerland and 20% from the European Union.

The vintage watches Davidoff sells are worth an average of 20,000 Swiss francs ($23,272) and could now be subject to another 6,000 Swiss francs in import tax.

JPMorgan analysts said they expected to see most pressure on the Swiss watchmakers, with both Cartier-owner Richemont and Swatch Group already on thin margins. Richemont did not reply to a request for comment. Swatch did not comment.

The U.S. is Switzerland's top foreign watch market, accounting for 16.8% of exports, or 4.4 billion francs worth, according to Federation of the Swiss Watch Industry.

Davidoff said he sells on average about 250 vintage watches by Rolex, Piaget and Patek Philippe annually and that the U.S. accounts for 60% of his business.

"I'm assuming that retailers are freaked out over there too," said Davidoff. "It is just going to put the market into complete freeze, or free fall."

TENSION

At a large conference hall in Geneva on Thursday where thousands of people flocked to admire the latest products being promoted by Swiss brands like Rolex, Cartier and Chopard, industry insiders were fretting about the future.

"It's been tense. Some meetings with Americans have been cancelled. Sales will surely be down. The year ahead doesn't look very promising for the watch industry," said Clement Fehrenbacher of Le Cercle des Horlogers.

The Neuchatel-based company manufactures the small parts inside watches for big watch brands in Switzerland.

"It'll be very difficult to get new projects if the market doesn't recover," Fehrenbacher said. "One of our clients is American, and we're waiting to see."

Behind the steady flow of champagne and glittering watches at the conference, concern was palpable among watchmakers after an already challenging 2024, which saw sales to China, the no. 2 market, decline by more than a quarter.

Many of the big names setting out their stalls in Geneva opted to remain silent about Trump's trade measures.

Vacheron Constantin marked its 270th birthday at the Watches and Wonders show by presenting an intricate new wristwatch boasting more than 1,521 component parts. But it declined to comment on the tariffs, as did those of other famous names.

"The U.S. market is absolutely critical," said David Sadigh, founder and CEO of Digital Luxury Group, a business consultancy. "With potential slowdown domestically in China, I think that you can feel some nervousness."

($1 = 0.8566 Swiss francs)

(Additional reporting by Oliver Hirt; Editing by Dave Graham and Bill Berkrot)