Tesla Inc.’s (TSLA) apparent market leading status in autonomous driving is an illusion fueled by the electric car maker’s willingness to put insufficiently tested vehicles on the road, prominent billionaire investor David Einhorn has claimed.

In a letter to investors, reported on by Business Insider, Einhorn’s $7 billion hedge fund Greenlight Capital lashed out at Tesla, dismissing CEO Elon Musk’s claims of technological prowess and predicting that it is only a matter of time before the Palo Alto, California-based company is overtaken by more capable and established auto manufacturers.

"Some of TSLA's presumed market lead in areas like autonomous driving may more likely reflect TSLA's willingness to put inadequately tested and dangerous products on the road rather than a true technological advantage," said Greenlight, which has made a hefty loss shorting Tesla’s stock. “While the CEO makes bold claims about TSLA's superior prowess, continued production shortfalls, defects and product recalls disprove him. TSLA faces competition from established OEMs that have decades of scale manufacturing experience.”

Einhorn, who shot to fame after shorting Lehman Brothers before its collapse, pointed to Tesla’s latest quarterly results as an indicator that all is not well at the company. While investors continue to believe that Tesla is on the brink of greatness, the New York City-based hedge fund claimed that a closer look at the company’s result statement showed that demand for its cutting-edge products is clearly faltering. (See also: Case Study: The Collapse of Lehman Brothers.)

“Tesla had an awful quarter both in its current results and future prospects,” Greenlight wrote. “In response, its shares fell almost 6 percent. We believe it deserved much worse. So much went wrong for TSLA in the quarter that it is hard to only provide a brief summary. The main near-term problems are poor demand for its legacy vehicles and manufacturing challenges for the new Model 3."

Greenlight went on to add that Tesla has mainly blamed lower gross margin assumptions on costs associated with ramping up the production of its new Model 3 sedan. The hedge fund believes these problems run even deeper, pointing out that notable price cuts were introduced on its legacy models, with limited success.

“TSLA dramatically reduced its gross margin assumption for the September quarter and publicly blamed ramp-up costs for the new Model 3 sedan,” Greenlight wrote. “More quietly, the company used the lower gross margin hurdle to offer incentives and to lower the cost of options on the Model S and Model X vehicles, and even offered significant markdowns on showroom models. Given the depth of the price cuts, we were surprised that demand for the Model S and Model X only improved modestly.” (See also: Tesla Recalls 11,000 Model X SUVs.)

Tesla representatives weren't immediately available to comment on Greenlight's comments. Aside from Tesla, the hedge fund is also shorting Amazon.com Inc. (AMZN) and Netflix Inc. (NFLX). (See also: Einhorn's Greenlight Capital Loses $400 Million to Investor Outflows.)