Tesla is no Apple.

That's according to David Einhorn, the founder of the hedge fund Greenlight Capital, who wrote out a litany of reasons he's bearish on Tesla in his firm's second-quarter letter.

"Tesla bulls look at Elon Musk, think of Steve Jobs, and decide Tesla is the next Apple," Greenlight wrote in the letter, which was reviewed by Business Insider.

Greenlight, which is short Tesla, then argued that's not the case:

"When Apple launched the iPhone, it was immediately profitable," Greenlight wrote. But Tesla "does not make money selling cars and Mr. Musk shows little interest in profits."

"When one person buys an Apple product, it makes the experience for other Apple customers better by supporting the developer ecosystem. This network effect attracts a stable and growing user base. TSLA is unlikely to sustain a competitive advantage by having a network of charging stations or by accumulating driver data."

"Competition was very slow to develop for Apple ... By contrast, every major car company in the world intends to compete with TSLA in electric vehicles."

"Steve Jobs attracted and retained a senior team of loyal lieutenants who implemented his vision ... Mr. Musk is a one-man show (and one distracted with many ventures at that)."

Greenlight is long GM, meanwhile, and sees the car companies as opposites.

"GM is capitalized to survive any foreseeable downturn," Greenlight said, citing billions of dollars in free cash flow, among other reasons. Tesla, it said, "is capitalized to survive only the next three quarters."

"GM bears are focused on the overhang from leased vehicles returning to the market ... Tesla faces the same risk and then some. 2014 was the first year of Tesla's three-year leasing program. Already, many of those cars are hitting the resale market at surprisingly low prices."

Performance has waned for Greenlight recently, however. The firm's funds dropped 2.8% after fees through the end of the second quarter this year, compared with a 9.3% return in the S&P 500 index, according to its letter.

Investors have since asked to pull some of their money. Greenlight was forced to return $400 million by midyear, The Wall Street Journal reported.