By Toby Sterling

AMSTERDAM (Reuters) - Top computer chip equipment maker ASML has decided to stop publishing the most closely-watched figure in its quarterly financial results, new order bookings, saying it is too "lumpy" and leads to excessive volatility in its share price. 

The Dutch company says its own forecasts are a better guide, as they are based on discussions with chipmakers about their capacity plans, in which ASML's circuit-printing machinery plays a major role.

New orders can take between around six and 18 months to fill, making it hard to interpret how each quarter's figures will play out - sometimes causing big stock price moves. 

"The swing factor is significant," Chief Financial Officer Roger Dassen said.

Analysts said the company's decision - announced on Wednesday as its stock spiked 7% due to better than expected fourth-quarter bookings - was partly regrettable, but mostly understandable.

"There is downside for investors, as ... (at present) we can monitor how average bookings are moving and whether we are getting confidence in the backlog for the next 12+ months," said Sara Russo of Bernstein.

"I do agree with ASML that in the context of a single quarter of bookings, it’s not a very useful measure of the longer-term health and stability of the business." 

Fourth-quarter bookings of 7.1 billion euros ($7.4 billion) compared to the third quarter's 2.6 billion euros. The big difference was likely timing of orders from top chipmaker TSMC of Taiwan, which this month announced plans for $38 billion in capital spending in 2025. 

"Capex for large spenders TSMC, Intel, and Samsung already tells you enough," said Degroof Petercam analyst Michael Roeg, who said he was okay with ASML's decision despite initially viewing it as a step backward in transparency.

In 2024, ASML shares surged more than 30% and then handed back all of those gains, but Dassen noted the company's full-year sales and margins wound up in line with forecasts the company had issued last January.

"If you put all those quarters together, you see it wasn't too shabby, was it?" he told reporters.

($1 = 0.9608 euros)

(Reporting by Toby Sterling; Editing by Mark Potter)