(Reuters) -Applied Materials ( AMAT ) forecast fourth-quarter revenue below estimates on Thursday, citing bumpy demand from clients amid economic uncertainty, sending its shares down 11% in extended trading.

U.S. President Donald Trump's ongoing global tariff negotiations, coupled with certain export restrictions to China, have stoked economic uncertainty and weighed on new orders for chipmaking tools suppliers such as Applied Materials ( AMAT ).

Tightened export controls on advanced semiconductor manufacturing equipment to China prevent these companies from selling their most cutting-edge tools to Chinese customers.

"We are expecting a decline in revenue in the fourth-quarter driven by both digestion of capacity in China and non-linear demand from leading-edge customers given market concentration and fab timing," CFO Brice Hill said in a statement.

Applied expects revenue of $6.70 billion, plus or minus $500 million, for the fourth quarter, compared with analysts' average estimate of $7.33 billion, according to data compiled by LSEG.

Its third-quarter revenue rose 8% to $7.30 billion, beating estimates of $7.22 billion.

Dutch firm ASML, the world's biggest supplier of chipmaking equipment, warned earlier in July that it may not achieve revenue growth in 2026 as chipmakers building factories in the U.S. await clarity on the potential impact of tariffs.