Billionaire investor David Einhorn’s Greenlight Capital has slammed Tesla Inc. in a recent letter to investors, saying that the Silicon Valley car maker’s prowess in driverless cars could mean just a willingness to put “dangerous products on the road.”

Tesla TSLA, -4.82% faces competition from established car makers that have decades of experience in scale manufacturing, Greenlight Capital said in a letter dated Oct. 24.

Some of its lead in self-driving cars “may more likely reflect (Tesla’s) willingness to put inadequately tested and dangerous products on the road rather than a true technological advantage,” it said.

Elsewhere in the letter, which also had some choice words for Amazon.com Inc. AMZN, +3.36% and Netflix Inc. NFLX, -0.46% , Greenlight said that Tesla had “an awful quarter” and it “deserved much worse.”

“So much went wrong for (Tesla) in the quarter that it is hard to only provide a brief summary,” Greenlight Capital said. Near-term problems include poor demand for existing vehicles, and “manufacturing challenges” for the Model 3, the hedge fund said.

The letter went on to call out Chief Executive Elon Musk.

“While the CEO makes bold claims about (Tesla’s) superior prowess, continued production shortfalls, defects and product recalls disprove him,” Greenlight said.

Tesla did not immediately return a request for comment.

The car maker is scheduled to release third-quarter earnings on Nov. 1, and analysts polled by FactSet expect Tesla to report an adjusted loss of $2.28 a share on sales of $2.95 billion. Shares have gained nearly 59% in 2017, far outstripping gains of 15% for the S&P 500 index. SPX, +0.38%

Greenlight is no stranger to controversy. Earlier this year, the hedge fund put pressure on General Motors Co. to split the stock in two classes, an idea rebuffed by the company and later on rejected by shareholders.

In the letter, the hedge fund also criticized Netflix for accelerating its cash burn “as it desperately tries to compensate for its inability to rely longer-term on licensed content.”

Amazon revealed “a much lower level of long-term structural profitability,” Greenlight said. “Our view is that just because (Amazon.com) can disrupt somebody else’s profit stream, it doesn’t mean that (Amazon.com) earns that profit stream.”