Shares of the electric vehicle maker are up nearly 700% over the last year, a meteoric rise that has punished short-sellers and turned it into the world's most highly-valued automaker.

The company's formal entry into the S&P 500 on Monday is expected to generate unprecedented activity near the close of trade on Friday as index-tracking funds load up on shares so their portfolios correctly reflect the index.

Still, Wall Street is divided over whether Tesla's days of heady gains are numbered.

Overall, Wall Street analysts have long been skeptical of Tesla. The 35 analysts tracked by Refinitiv have an average price target of $396.30 per share, which would represent a 36% decline from its current price. Yet in a sign of how split Wall Street is on the stock, target prices range from a high of $774 per share by Elazar Advisors to a low of $40 by GLJ Research.

Tesla closed Thursday at $655.90.

Some long-term investors say that they still expect to see Tesla post above-average gains due to increasing adoption rates in the global electric vehicle market and its solar energy business. At the same time, investors remain convinced that billionaire Elon Musk, the chief executive of Tesla, will continue to push the company's disruptive technology ahead of its competitors.

"It's become clear this year just how far ahead of the competition the company is in terms of not only its technological abilities but its combination of range and performance at an affordable price," said Gary Robinson, portfolio manager of the Baillie Gifford US Equity Growth fund, who owns the stock.

Tesla will likely prove to have a more profitable business model than its rivals and post accelerating growth rates in its solar business, allowing its stock to more than double over the next 5 years, he said.

Overall, Tesla trades at 175 times its estimated earnings per share over the next 12 months, compared with valuations at 14 times estimated earnings per share for BMW and 16 times estimates earnings for Toyota Motor Corp, according to a research note from JP Morgan.

At the same time, Tesla is expected to earn $2.29 per share on $30.8 billion in revenue during its current fiscal year, while General Motors is expected to earn $4.67 per share on $120.7 billion in revenue, according to Refinitiv.

Its inclusion in the S&P will push the forward price to earnings ratio of the S&P 500 index up an additional 0.4 times to near its highest valuation in history, according to a note from Goldman Sachs.

"Tesla's multiple of earnings is very high in nominal terms for any company in any industry at any time in history," the firm noted, keeping its $80 price target on the company's shares.

Despite the stock's high valuations, some long-term investors say that they are sticking with the company. "Near term valuations tend to be less meaningful over time when you invest in right teams," said Anthony Zackery, a portfolio manager at Zevenbergen Capital Investments.

Bears still abound in Tesla, focusing on Musk's track record of missed production targets, and on corporate governance risk after Musk was forced to step down as chairman to settle fraud charges in 2018.

Despite handing short sellers $33.8 billion in mark-to-market losses since the start of the year, Tesla remains the company with the most total money bet against it in the U.S. market, according to S3 Partners.

"At some point you do short the stock because this is probably the last big move for a while for Tesla," said Charles Lemonides, portfolio manager of ValueWorks LLC, who does not currently have a position in the company.

"Up until now betting against Tesla has been a very dangerous thing to do, but it may get to a place where it's completely overextended," he added.

(Reporting by David Randall; additional reporting by Noel Randewich, editing by Megan Davies, Ira Iosebashvili and Richard Pullin)

By David Randall