Netflix on Thursday reported cooling subscriber growth as fierce competition and the pandemic weigh heavy despite hits like "Squid Game" and "Money Heist."

The streaming service ended the year with 221.8 million subscribers, just below target, after booming during coronavirus lockdowns that kept people at home and on the platform.

Things are not looking better for the first quarter of 2022, with the Netflix earnings report saying the firm expected to only add some 2.5 million subscribers.

The market punishment was immediate, with shares of the California streaming giant losing some 20 percent in after-hours trading.

The last first-quarter expectation under 2.5 million subscribers came in 2010, when Netflix had a mere 13.9 million customers.

"While retention and engagement remain healthy, acquisition growth has not yet re-accelerated to pre-Covid levels," Netflix reported.

"We think this may be due to several factors including the ongoing Covid overhang and macro-economic hardship in several parts of the world," it added.

Most of the 8.3 million subscriptions added at the end of last year came from outside North America, according to the streaming service.

Netflix argued that it was holding its own against fierce streaming competition from the likes of HBO Max and Disney+, saying it "may be affecting our marginal growth some."