It is unclear whether Musk plans to bring someone in to run Twitter, but his foray into the social media sector comes as he already leads four companies: Tesla, SpaceX, Neuralink, and the Boring Company.

Musk has stated intentions to take Twitter private once his takeover of the firm is complete, saying that he wants to make the social network “a platform for free speech”—and suggesting he would have at least some input on how the company is run.

But after the deal was confirmed on Monday, Tesla shares plummeted, suggesting apprehension among investors as uncertainty remains about how much time Musk might devote to Twitter once his takeover of the company is complete.

Zoe Gillespie, an investment manager at Brewin Dolphin, said the drop in Tesla share prices was a reflection of investors’ concern about Musk’s presence at the electric vehicle firm being diluted.

“I think investors [wonder] whether the depth of the Tesla board’s going to be potentially dragged into Twitter,” she told Fortune. “Whether it’s just a short-term thing until the lay of the land is determined, the market hasn’t viewed it positively because I think there are questions around whether the deal could impact on top [Tesla] executives as well, and whether the focus will still be on Tesla.”

Mike Rhodes, CEO and founder of London-based consultancy firm ConsultMyApp, told Fortune on Tuesday that Twitter the deal could “prove to be a bridge too far” for Musk.

“The projects he has on the go both at Tesla and SpaceX can hardly be seen as unambitious tasks that require little more than passive management,” he told Fortune on Tuesday. “Jumping onto yet another challenging expedition, one can only assume that some of the earlier energy he injected into those firms will be lost in the process.”

Rhodes added that Tesla and SpaceX may lose some of Musk’s “pizzazz” if he chooses to focus more on his new venture, which he speculated could ultimately result in lower performance or falling share prices.

Tesla share price at risk?

Tesla shares were trading around 9% lower on Tuesday.

Richard Windsor, founder of research firm Radio Free Mobile, told Fortune on Tuesday that while Musk’s purchase of Twitter is an “excellent deal” for Twitter’s current shareholders, it raises the risk for Tesla shareholders.

“There is obviously the management time, but quite frankly, if you look at Tesla and you look at what he’s likely to do with Twitter, I suspect that’s not going to be too much of an issue,” he said in a phone call.

But Windsor, who said he was “the last person to say that Tesla is fairly valued,” told Fortune that Tesla share prices could normalize if its famed CEO was less involved in the company.

“If Musk did step back a little bit from Tesla, the shine or the appeal of the shares might diminish, and consequently, the shares might sell down somewhat,” he said.

‘Likely to emerge bruised but in fighting form’

Meanwhile, AJ Bell investment director Russ Mould said Tuesday that there were a number of issues surrounding Musk’s acquisition of Twitter.

“Given how Musk’s energies are already spread across Tesla’s car and solar energy operations and SpaceX, loyalists are unlikely to be concerned about the serial entrepreneur giving himself something else to do,” he said.

Mould also noted that Musk was taking “a good deal of risk” by using Tesla shares as collateral.

“If the electric car maker’s shares were to unexpectedly crater, that could create a lot of discomfort, even if his 2018 pay deal allows him to exercise options priced at just $70 a pop and he is, on paper, the world’s wealthiest person,” he said.

Windsor agreed that it was important to bear in mind that Musk has used part of his stake in Tesla to secure financing for the purchase of Twitter, and that pinning Tesla stock to the deal created a new risk for Tesla share prices.

Susannah Streeter, senior investment and markets analyst at Hargreaves Lansdown, told Fortune that Musk faces an “extremely hard slog in the months and years ahead” at Twitter, with regulatory crackdowns on Big Tech and maintaining revenue at the company likely to require his attention.

“[But] given that Musk has time and time again deflected blows of criticism aimed at his perceived overambition, he is likely to emerge bruised but in fighting form, whatever obstacles are thrown at him,” she said.