Feb 13 (Reuters) - Applied Materials AMAT.O forecast second-quarter revenue below market estimates on Thursday, expecting escalating geopolitical tensions to weigh on sales of its chipmaking equipment, sending its shares down more than 5% in extended trading.

Revenue from China, Applied's largest market by revenue share in the first quarter, is threatened by tighter U.S. restrictions on exports of chipmaking technology.

Such curbs will hurt 2025 revenue by about $400 million, Chief Executive Officer Gary Dickerson said on a post-earnings call. Half of this impact will be seen in the second quarter, financial chief Brice Hill said on the call.

This represents about 1.4% of the $29.18 billion analysts expect Applied to record in fiscal 2025 revenue, according to data compiled by LSEG.

The U.S. government said in December that new controls will be placed on the export of semiconductor manufacturing equipment needed to produce advanced-node chips to China.

"The ability of U.S. companies to serve the China market is constrained and has been further limited by updated trade rules," CEO Dickerson said.

Applied Materials forecast second-quarter revenue of about $7.1 billion, plus or minus $400 million, compared with the estimates of $7.21 billion

Half of the impact from trade restrictions to 2025 revenue is expected in the services segment, under which the company provides upkeep and optimization for machinery, the executives said, as the company is unable to address some customers in China.

Sales to China accounted for about 31% of Applied Materials' total first-quarter sales, down from about 45% of total revenue in the year-ago period.

Earlier on Thursday, U.S. President Donald Trump also tasked his economics team with devising a plan to impose reciprocal tariffs on every country that imposes duties on U.S. imports, targeting China, Japan and South Korea — some of Applied's largest markets.

This has offset the positive impact of a rise in demand for advanced chips capable of processing the vast data employed by generative AI.

Applied expects second-quarter adjusted profit of $2.30 per share, plus or minus 18 cents, in line with estimates of $2.30 per share.

The company reported first-quarter revenue of $7.17 billion, beating estimates.