Investors and analysts are looking sceptically at computer chip equipment maker ASML , they said on Wednesday, after the company cut 2025 financial guidance, citing weakness in markets other than AI and delayed orders.

The position of ASML, Europe's most valuable technology company, as an essential supplier to chipmakers is not in question. But doubts have emerged over short-term sales, and, for the longer term, whether it can continue to outgrow the overall market.

Tuesday's change to guidance triggered the biggest selloff in ASML's shares in two decades.

Shares fell by another 4.9% to 635.60 euros at 0840 GMT on Wednesday. In July, it had reached an all-time high above 1,000 euros ($1,088) a share, the peak of a decade-long surge based on ASML's dominance of the market for lithography tools, needed to create circuitry.

ASML's executives are expected to address analysts on a call later on Wednesday.

After the pandemic leap in demand, ASML said some customers have announced delays of new plants and upgrades, including makers of the logic chips used in smartphones, PCs and other devices.

Manufacturers that make the memory chips that go into them also plan fewer expansions, meaning they can rely on existing equipment for longer.

"There need to be limits to the expectations we investors put in any single company," said Nick Rossolillo of Concinnus Financial, who has owned ASML stock since 2022.

"That's especially the case for an upstream equipment supplier highly reliant on the spending plans of its manufacturing customers."

ASML did not identify which customers were behind the guidance cut, but analysts looked first at TSMC, which makes AI chips for Nvidia and smartphone chips for Apple.

"The strong sales trends at TSMC are a misleading indicator for the overall health of the semiconductor industry," said analyst Michael Roeg of Belgian investment bank Petercam Degroof.

"TSMC has been spending rather low capex numbers so far this year, and they may do so again next year because their overall (plant) utilisation is not as good as their sales numbers suggest."

Among ASML customers that make logic chips, Intel said in August it would cut capital spending by $10 billion in 2025, while Samsung has said it faces challenges at the factory it is building in Texas.

Roughly a quarter of chipmakers' spending on tools goes to ASML, though some analysts say changes in chipmaking techniques could lead that to be lower.

Han Dieperink, chief investment officer at investment firm Aureus, said customer delays are also a negotiating tactic that may force pricing concessions from ASML, squeezing margins.

ASML remained a cornerstone investment, even though Aureus reduced its stake in August on valuation concerns, he said. He also cited declining orders from Chinese chipmakers as U.S.-led export restrictions bite.

"China of course knew the (restrictions) were coming and they front-loaded" purchases in the 2022-2024 period, he said.