Taiwan Semiconductor Manufacturing Co. (TSMC) has changed its outlook for 2018 revenue and capital spending, reflecting soft mobile and digital currency mining demand for the season, right before the launch of Apple's iPhones.

"Our second quarter business was mainly impacted by the mobile product seasonality, while the continuing strong demand from cryptocurrency mining and a more favorable currency exchange rate moderated the mobile softness," said Lora Ho, SVP and Chief Financial Officer of TSMC.

Chief Executive Officer C. C. Wei said sales will rise this year by a high single-digit percentage in U.S. dollar terms, down from an already reduced projection of 10 percent. That followed a disappointing third-quarter sales forecast from the world's largest contract chipmaker. It's predicting revenue of $8.45 billion to $8.55 billion in the three months ending September, short of the $8.68 billion projected.

TSMC also reduced its capital spending outlay for the year, to $10 billion to $10.5 billion from as much as $12 billion previously, signaling a slower pace of investment in technology and capacity expansion.

"Moving into third quarter 2018, we anticipate our business will benefit from new product launches using TSMC 7-nanometer technology while cryptocurrency mining demand will decrease from second quarter.

TSMC expects a bounce-back in smartphone demand this year. Apple, TSMC's biggest customer, typically unveils its latest phones in September but is coming off a disappointing performance for the much-heralded iPhone X.

In the second quarter, shipments of 10-nanometer accounted for 13% of total wafer revenue; 16/20-nanometer process technology accounted for 25% of total wafer revenue; and advanced technologies, defined as 28-nanometer and more advanced technologies, accounted for 61% of total wafer revenue.

TSMC will also begin cranking out next-generation 5-nanometer chips in large quantities only from the first half of 2020, Wei told investors, dashing expectations for a 2019 ramp-up.