Shares of Tesla (NASDAQ:TSLA) soared after CEO Elon Musk gave an upbeat forecast at the company's annual shareholders meeting. The comments, made after the market closed on Tuesday, sent Tesla's stock up 9.7% during trading on Wednesday.

But a big-name Wall Street analyst who has been bullish on Tesla for years isn't buying Musk's forecast this time around.

Tesla profit in 2018? Not likely, says Adam Jonas

The analyst in question is Adam Jonas, Morgan Stanley's lead automotive analyst. Jonas has become famous in investment circles for his very bullish (some would say "outlandish") forecasts for the Silicon Valley carmaker. Here's just one example: In April 2017, Jonas issued a note estimating Tesla's eventual total addressable market at $15 trillion, or about 20% of the gross domestic product of the entire world.

A black Tesla Model 3 sedan, said to be the first produced, is shown in front of Tesla's factory in Fremont, California.

Production of Tesla's Model 3 began in July 2017 with this car. But almost a year later, the production line still isn't up to speed. Image source: Tesla, Inc.

But it seems that Jonas's optimism has been greatly tempered. In a note issued on Thursday, he bluntly pointed out that several key points of the guidance given by Musk at the shareholder meeting are far more optimistic than Morgan Stanley's current estimates.

"It's really looking like we are going to have positive GAAP net income next quarter and as well as positive cash flow in Q3 and Q4," said Musk at the shareholder meeting. "And we, as I've said before, do not expect to need to raise any incremental debt or equity."

Jonas isn't buying any of that. "We currently forecast Tesla to post a GAAP net loss of $554 [million] [in the third quarter of 2018]. We do not forecast Tesla to achieve a positive GAAP operating profit until 2020, and we do not forecast a positive GAAP net profit until 2021," Jonas said in Thursday's note.

He isn't buying Musk's optimism around cash flow, either.

"Mr. Musk expects positive free cash flow in 2H'18. This is far more bullish than our forecast of $1.4 [billion] adjusted free cash burn in 2H'18," Jonas said. "We do not forecast Tesla to produce a positive free cash flow result until 2021."

Jonas also said that despite Musk's repeated insistence that Tesla won't need to raise any more cash, Morgan Stanley still expects the company to raise $3 billion in the third quarter, by issuing new stock at a price around $280. "If Tesla can get through 2018 without raising equity, it would represent a material upside surprise to investors," Jonas said.

Oh, and that 5,000 cars a week thing? Not buying that, either

In the near term, a critical point in the bullish case for Tesla is the rate at which it is able to produce the compact Model 3 sedan. Tesla has been working for nearly a year to get to a sustainable production rate of 5,000 cars a week.

Musk has said that's likely to happen around the end of June, which is something he reiterated at the shareholder meeting. But Jonas said that Morgan Stanley remains skeptical. "We do not expect a 5k/week run-rate of production before [mid-2019]... over one year from now," Jonas said.

The larger issue here is one that Jonas expressed in a note last month, when he first cut his price target for Tesla's shares to $291 from $376. It has taken Tesla nearly a year, several changes to the Model 3, and some drastic changes to its production line to even get within sight of that 5,000-per-week goal. All of those changes have cost a lot of money, and those costs will be amortized over the life of the Model 3.

The upshot is that the car's profit margin will almost certainly be much thinner than investors have been hoping, no matter how many of them Tesla manages to make in a week.

Jonas is still a Tesla bull, sort of

I should note that despite his recent comments, Jonas hasn't fully abandoned hope in Tesla. His current price target of $291 still includes a value of $95 per share on what he calls "Tesla Mobility" -- a future automated shared-mobility business.

The thing is, as far as we know, "Tesla Mobility" consists of little more than an idea and a few promises made by Musk. Not only will Tesla need to build a network infrastructure to support such a business, it will also have to develop a reliable full self-driving system -- something that Musk has repeatedly promised, but something that seems a long way off. Apparently, Jonas hasn't quite let go of the idea.

At this point, if Tesla delivers on Musk's promises without needing additional billions in outside capital, it will be a huge surprise. But it looks like even Adam Jonas is preparing for the increasingly likely possibility that it won't.

John Rosevear has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Tesla. The Motley Fool has a disclosure policy.