GM's 2020 profit shocked Wall Street -- and GM. That's bad news for 2021

Last year, GM and other automakers were hurt by pandemic-fueled temporary plant closures earlier in the year. Those closures, in combination with mass job losses and a shift to working from home, slammed the brakes on auto sales in the spring.

But car sales at both GM and across the industry bounced back sooner than anyone expected. A few factors boosted the demand for cars, including the improving economy, a safety-minded reluctance to use car-hailing services or public transit, and some people moving out of cities.

The bounceback caught GM and its rivals off guard, and they're paying the price. Automakers cut back computer chip orders early last year, and electronics manufacturers, which had strong sales during the pandemic, happily snapped up the excess supply. But when car sales bounced back, it left the industry struggling with a chip shortage.

GM on Tuesday announced the extension of a one-week shutdown at three North American plants. The shutdown was scheduled this week because of the chip shortage, but GM now says it will last through at least mid-March.

That weighed on GM's 2021 earnings guidance, hurting its production, earnings and cash flow in 2021. The company didn't provide specifics but gave a range that suggested earnings could drop from 2020 levels. And earnings before items, including interest and taxes, are expected to be less than Wall Street forecasts.

Last week, GM rival Ford said that its first quarter production would be cut by between 10% to 20% because of chip scarcity. If that extends into the second quarter could cost the company between $1 billion and $2.5 billion in 2021.

GM on Wednesday posted stronger-than-expected fourth-quarter earnings, which helped its full-year 2020 profit to beat 2019's earnings -- despite the pandemic.

Shares of GM were little changed in pre-market trading on the report. Shares are up 10% since January 29, when the company announced it hopes to sell only emission-free vehicles by 2035.

The nation's largest automaker earned $2.8 billion in the quarter, excluding special items. That topped Wall Street's forecasts of $2.6 billion. Quarterly revenue rose 22% to $37.5 billion, also beating expectations.

Overall in 2020 the company earned $7.1 billion excluding special items, up from $6.9 billion in 2019, when a six-week strike cost it $2.9 billion.

Those special charges in 2020 included a $1.2 billion charge for fixing airbags made by Takata, and a gain in the value of its investment PSA Group, which merged with rival Fiat Chrysler, as well as a gain on its investment in Lordstown Motors, which plans to use a former GM factory to build electric trucks.

GM ended the year with increased fourth quarter sales in China and the United States, its two largest markets, and global sales were up 4% in the period. That still left full-year sales down 11% compared to last year, to 6.8 million. Like GM, most major automakers also reported a drop in sales.