Morgan Stanley is telling its clients Elon Musk's stake in SpaceX may be leveraged as a source of funding for his plan to take Tesla private.

Musk is founder and CEO of SpaceX and Tesla.

"Elon Musk's desire to potentially take Tesla private may require large amounts of new equity capital. We see scope for SpaceX to play a potentially crucial role in facilitating the required financing as well as the strategic narrative going forward," analyst Adam Jonas said in a note entitled "How SpaceX Can Potentially Help Tesla Go Private" to clients Monday. "We believe investors should consider the potential role of SpaceX in the near-term financial options confronting Tesla and its shareholders."

On Monday, Musk explained that his conversations with the Saudi Arabian sovereign wealth fund were a driver behind his "funding secured" tweet on Tesla's corporate blog.

Tesla shares surged 11 percent last Tuesday after he tweeted that he is considering taking the company private at a $420 per share price. In a blog post later that day, Musk said "the intention is not to merge SpaceX and Tesla."

Despite the comment, Jonas said SpaceX could invest directly in Tesla as part of a strategic partnership.

"While we are in no position to dispute this statement on a merging of the two entities, we do not expect Elon Musk to rule out the potential for the involvement of SpaceX as a capital-providing strategic partner or the potential for the value of SpaceX equity held within Mr. Musk's trust to be considered in the financing of a potential Tesla buyout," Jonas said. "We see increasingly compelling areas of industrial and strategic cooperation between SpaceX and Tesla in telecommunications / satellite broadband which we see as potentially advantageous for shared and automated transport networks."

Jonas said Musk's 54 percent stake in SpaceX could be worth more than $15 billion, using the company's latest funding round valuation. The analyst speculates Musk could use his SpaceX stake as collateral in a Tesla buyout.

"We do not have knowledge of how much of Elon Musk's SpaceX shares (if any) are currently pledged as collateral for any existing loans," he said. "Nevertheless, we believe this potentially substantial store of value for one of the largest and well known private companies in the world is highly relevant to this discussion."

The analyst reiterated his equal-weight rating and $291 price target for Tesla shares. It was trading above $352 a share on Monday.

Jonas was known for having some of the most aggressively bullish predictions for Tesla's ambitions, including a 2016 note highlighting an Uber-like transport service with autonomous electric vehicles. But the widely followed auto analyst became less optimistic over the carmaker's shares, starting in May 2017.

Tesla declined to comment on the Morgan Stanley report beyond referring to Musk's two recent corporate blog posts on the "Taking Tesla Private" topic.