(Reuters) -American media stocks tumbled on Monday after President Donald Trump unveiled a 100% tariff on all movies produced outside the U.S., a move that could sharply raise costs for Hollywood studios and rattle the global entertainment industry.

Trump's announcement was short on details. It did not say whether the levies will target films on streaming platforms and those shown in theaters, nor did it specify if the tariffs will be calculated based on production costs or box office revenue.

Streaming pioneer Netflix ( NFLX ) could particularly be at risk, analysts said, as it relies on its global production network to produce content for international audiences. Its shares fell 4.9% in premarket action, leading a slide in media stocks.

Despite Los Angeles' longstanding reputation as the hub of cinema, studios have over the years shifted production overseas to locations such as the UK due to attractive tax breaks and lower costs. None of the 10 best picture contenders for this year's Oscars were filmed in the Californian city.

A forced move back to the U.S. would likely drive up production budgets for an industry that now relies on a global supply chain - with shoots in Europe, post-production hubs in Canada and visual effects teams spread across Southeast Asia.

Walt Disney Co ( DIS ), Warner Bros Discovery ( WBD ) and Universal-owner Comcast ( CMCSA ) were down between 0.8% and 2.7%.

"The problem is that pretty much all the studios are moving tons of production overseas to reduce production costs and leverage foreign credits," said Rosenblatt Securities analyst Barton Crockett. 

"Raising the cost to produce movies could lead studios to make less content. There's also a risk of retaliatory tariffs against American content overseas." 

American movies generated $22.6 billion in exports and a trade surplus of $15.3 billion in 2023, according to the American Motion Picture And Television Industry.

A survey conducted by ProdPro among studio executives regarding their preferred production locations for 2025 to 2026 showed that the top five choices were all outside the U.S.

(Reporting by Harshita Mary Varghese in Bengaluru; Editing by Sriraj Kalluvila)