Tesla has lost nearly a third of its value this year but Morgan Stanley believes there are some pieces of Elon Musk's company that investors do not value properly, most notably its self-driving technology unit.

"We believe investors underappreciate / undervalue Tesla's Autonomy business," Morgan Stanley analyst Adam Jonas said in a note to clients Tuesday. He is widely followed on Wall Street due to his early bullish call on Tesla, as well as his attention to the growing electric vehicle market.

Jonas' optimism comes as the stock slowly rebounds after its steady fall this year. Tesla shares dropped as far as $179 a share at the beginning of June, shortly after Jonas held a conference call with investors where he said "Tesla is not really seen as a growth story." Jonas said Tesla seems more "like a distressed credit and restructuring story" but warned that a big technology company like Amazon or Apple is not going to come to the rescue. Tesla shares dropped 6% the day of Jonas' call, continuing a slide begun when Musk sent an urgent email to employees to cut spending and take "hardcore" measures to rein in expenses.

But the last few months haven't been all bad, in Jonas' view, as he noted last week that the month of May saw Tesla continue "to extend its lead vs. a still-small group of true [electric vehicle] competitors." And, on Tuesday, the analyst said Morgan Stanley clients "are increasingly questioning us about areas of potential value within the company's portfolio that may be underappreciated by the market."

Jonas gave a list of the parts of Tesla he thinks are underappreciated by investors:

Autonomous (self-driving) technology

Tesla's infrastructure of charging stations

Solar energy products

Energy storage products

Sales of electric vehicle batteries to other automakers

China market opportunity

The value of government electric vehicle incentives

Tesla's coming Semi truck

These are all areas that have "potential commercial value beyond the manufacturing of Tesla vehicles," Jonas said. He believes the company's "Autonomy" unit is one of the most undervalued pieces, saying that "many investors to whom we speak do not explicitly include Tesla's Autonomy business in their valuation of the company." Jonas estimates that, on its own, the self-driving business is worth $8.5 billion. Morgan Stanley has a $230 a share price target on Tesla, with Jonas estimating that the autonomy business makes up a fifth of the company's total value at $45 a share.

Tesla shares rose about 2% on Tuesday to $217.1 from Monday's close of $212.88 a share.