- Tesla shares fell 5.6 percent Thursday, bringing losses for the week to 14.6 percent.
- The electric car maker's stock is down 20 percent from its all-time high in late June.
- Disappointing deliveries, safety concerns, Volvo competition and negative Wall Street commentary are the factors driving the shares lower.
What a difference a couple of weeks make. After hitting an all-time high in late June, Tesla shares have collapsed 20 percent as of Thursday's close, due to mounting concerns about its sales results, competition and the safety of its cars.
Traders consider a 20 percent decline from an all-time high the technical definition of a bear market move.
The electric car maker's stock fell 5.6 percent Thursday, bringing losses for the week to 14.6 percent.
"Tesla's stock was pushed to ridiculous levels on the notion that the Model 3 would be a slam-dunk success," said Fred Hickey, editor of High Tech Strategist. The company's "$100,000+ models aren't selling as well and are piling up in inventory (the relatively small pool of potential buyers at these prices may be exhausted). This bubble stock is losing air rapidly, as it should."
Multiple Wall Street firms including Goldman Sachs, Bernstein, KeyBanc Capital and Cowen expressed disappointment over Tesla's second-quarter delivery results in notes to clients the last two days.
Goldman analyst David Tamberrino cited how Tesla's second-quarter deliveries number released Monday of approximately 22,000 cars missed his forecast of 23,500 and the Wall Street consensus of 24,200.
Tesla blamed a production issue with its 100 kilowatt-hour battery packs for the second-quarter deliveries shortfall.
"Tesla's Q2 production and deliveries report raised more questions than answers, particularly about Model S and X demand," Bernstein's Toni Sacconaghi wrote in a note to clients Wednesday.
After the weaker-than-expected deliveries number, Volvo announced Wednesday that it will phase out combustion engine-only cars. The automaker's new cars will be all electric or hybrid by 2019.
"This announcement marks the end of the solely combustion engine-powered car," Volvo Cars Chief Executive Hakan Samuelsson said, according to a Reuters report.
The Volvo news came after a Handelsblatt Global article last week, which said BMW plans to introduce an electric version of its popular 3-Series line of sedans later this year.
In addition to the rising competition, one of the key selling points for Tesla's cars is now being called into doubt.
On Thursday, the Insurance Institute for Highway Safety's Dave Zuby questioned Tesla's claim that the Model S is the safest car in history after a series of new crash tests.
"If you're looking for top-line safety, we believe there are other, better choices than the Model S," Zuby told CNBC.
Tesla declined to comment on this story. Its shares are up 44.6 percent this year versus the S&P 500's 7.6 percent return through Thursday.
The company's market value is about $50.7 billion, which is now below General Motor's $52.7 billion, according to FactSet.
Tesla CEO Elon Musk had bigger concerns than the company's falling stock price Thursday morning.