A long, drawn-out fight between Tesla Inc. Chief Executive Elon Musk and U.S. securities regulators may turn out to be the best thing for the car maker, despite the fallout from a securities-fraud lawsuit dragging on the stock Friday.

A day after the Securities and Exchange Commission filed a lawsuit against Musk, experts agreed Friday that the regulators’ action had been surprisingly swift and tough. This was no slap on the wrist: Musk will have to bear some responsibility, although few believe the case could mushroom into a criminal complaint.

Tesla TSLA, +5.04% shares fell 13.9% to end at $264.77 on Friday, their largest single-day percentage loss in nearly five years and the lowest prices since Sept. 7. The stock was the worst performer on the Nasdaq and was off more than 30% from a $385 record close in September 2017.

Read more:The SEC vs. Elon Musk — What the lawsuit means for Tesla investors

The Securities and Exchange Commission suit, filed Thursday, seeks to bar Musk from serving as a director and officer of a publicly traded company. It accuses him of misleading investors and committing securities fraud when he tweeted on Aug. 7 that he had “funding secured” to take Tesla private at $420 a share, and doubled down on the claim on subsequent exchanges.

Musk reportedly walked out of settlement talks at the last minute before the charges were levied. Settlement terms, according to various media reports, included requiring Musk to pay a fine and be barred from leadership roles in public companies for two years. The suit could, of course, settle at any time; barring that, it would take at least a couple of years to wind its way in the court system.

Seeking to ban Musk from his key roles — he is Tesla’s chairman as well — was an “aggressive opening” for the regulators, Columbia University law professor Joshua Mitts said.

“I’m proud of the SEC,” as the lawsuit showed it was not afraid to take on a popular business leader, he said. For a criminal case to arise, however, “this would have to feel like Bernie Madoff,” a clear case of defrauding investors, while there’s room to argue it could have been a mistake on Musk’s part, Mitts said.

Opinion: If Tesla had a real board, it would remove Elon Musk as CEO

Marcel Kahan, a law professor at New York University, also believed a criminal case against Musk would be unlikely, as there is no evidence Musk enriched himself or directly defrauded people. The SEC complaint, on the other hand, seems to be on solid footing.

In rejecting a settlement, “Musk is basically saying ‘make my day, I don’t believe you,’ ” Kahan said. The purported settlement, moreover, would have taken Musk out of Tesla at a critical juncture for the company; choosing to fight it buys the company and Musk time to somewhat plan ahead, he said.

Tesla’s promises for the second half of the year include becoming profitable and able to produce 50,000 to 55,000 Model 3 sedans in the third quarter.

The SEC indeed appears to have a strong case against Musk, said Andrew Vollmer, a law professor at the University of Virginia. Musk might be able to argue that he in good faith thought he had funding secured to take Tesla private, but the SEC allegations indicate it wouldn’t be a strong response against the claims, he said.

Vollmer, who served as SEC deputy general counsel, said he was surprised and concerned about the severity of the sanctions the SEC seeks. Going after a director-and-officer bar seems “disproportionately harsh” for the episode involving the tweets about going private, even though that was serious, he said.

Such bans are not meant to punish, but to protect the future of a company and its shareholders, and in the case of Tesla it would deprive shareholders of an important leadership, Vollmer said.

See also: Why legal experts say the SEC has a strong case against Musk

For Santa Clara University law professor Steve Diamond, choosing to fight the suit and eschewing a settlement was like “rolling the dice with your life.”

What’s more, the SEC complaint, as detailed as it was, could lay out a basis for a criminal complaint by the Justice Department, he said. Martha Stewart did less to harm her company’s investors, and she got banned from the company she founded and jail time, he said.

Musk for weeks, if not months, had railed against Tesla short sellers, Diamond said.

The shares rallied 11% on Aug. 7, triggering massive short squeezes for those who bet against Tesla. They are off 15% this year, which contrasts with advances of 9% and 7% for the S&P 500 index SPX, +1.59% and the Dow Jones Industrial Average. DJIA, +1.33%

“I question if it’s going to be a going concern if (Musk) is no longer the CEO,” said Scott Kollman, a lecturer in finance and economics at San Diego State University.

Opinion: The SEC may be doing Tesla a favor with its lawsuit

Musk, Tesla’s largest shareholder, would still yield power at the company, but if he is to be removed completely there’s doubt whether it could survive, he said.

“The company doesn’t have the financial stability and balance sheet to last without him,” Kollman said.

Not being cash-flow positive, Tesla “doesn’t have any money to live from,” and would have much more trouble raising more capital without Musk at the helm, he said.

“The whole company relies on him,” and even short sellers, at the end of the day, bet against Elon Musk more than they bet against Tesla, Kollman said.