After three months as the nation's most valuable automaker, a bad week in an otherwise stellar year has knocked Tesla from the top perch.

Tesla's growth remains stellar, with shares soaring close to 50 percent this year, twice that at General Motors, which retook the spot Thursday. Ford Motor has fallen in value.

But a trifecta of bad news in recent days, starting with a tweet from Tesla CEO Elon Musk, has delivered the worst week for the electric automaker's stock since early 2016.

Shares fell 4 percent in midday trading Thursday, pushing shares down more than 13 percent for the week.

On Monday, Musk sent out tweet saying that the Palo Alto, Calif., company anticipates production of 20,000 Model 3 cars per month in December, which was below previous estimates. Tesla also said Monday that it delivered about 22,000 vehicles in the second quarter, bringing first-half deliveries to about 47,100. That's at the low end of the company's projections earlier this year of between 47,000 and 50,000 deliveries.

Then on Wednesday, the dynamics of the electric car market shifted when Volvo announced that by 2019 it would produce only electric and hybrid vehicles. Volvo, which is based in Sweden but owned by Chinese firm Geely, will launch five fully electric cars between 2019 and 2021. Three of them will be Volvo models and two will be electrified cars from Polestar, Volvo Cars' performance car arm.

General Motors is already selling the Chevrolet Bolt, Audi plans to introduce an electric SUV next year. Ford will have one by 2020.

On Thursday, one day after the Volvo announcement, the Insurance Institute for Highway Safety said that while Tesla's Model S received an acceptable rating in its small overlap front test, it did not get the Top Safety Pick+ rating that the Lincoln Continental, Mercedes-Benz E-Class and Toyota Avalon received.