Tech firms have been at the forefront of a global surge in equity markets for the past two years as they pumped cash into all things linked to artificial intelligence

Asian markets dropped Monday as concerns about the AI-fuelled tech rally returned to the spotlight after weak earnings from two big-name firms last week revived questions about the wisdom of the vast sums invested in the sector.

Tech firms have been at the forefront of a global surge in equity markets for the past two years as they pumped cash into all things linked to artificial intelligence, with chip giant Nvidia becoming the first to top $5 trillion in October.

But they have hit a sticky patch in recent weeks amid worries that their valuations have gone too far and the AI investments will take some time to make returns, if at all.

Those concerns were compounded last week following disappointing earnings from Oracle and Broadcom.

Tokyo and Seoul, which have chalked up multiple record highs this year on the back of the tech surge, led losses Monday, while there was also selling in Sydney, Singapore, Wellington and Taipei. Shanghai was flat with investors unmoved by another round of weak Chinese consumer data.

Among the biggest losers were South Korean chip giants Samsung and SK hynix, while Japanese tech investment titan SoftBank tanked more than 7%.

Friday sees the Bank of Japan’s policy decision, with forecasts for a rate hike, though analysts were cautious on the outlook.

The central bank will frame Friday’s move as a response to a stronger economy and more durable inflation, wrote analysts at Moody’s.

They added: A solid December Tankan survey of Japanese business sentiment early in the week and sticky consumer price inflation data on Friday will reinforce that narrative, but the real driver will be the weak yen.