WASHINGTON—After a social media post by a well-known public figure caused shares of a public company to plummet in value last week, some legal analysts considered the question: Can celebrities trade on tweets?

“Sooo does anyone else not open Snapchat anymore? Or is it just me… ugh this is so sad,” tweeted Kylie Jenner, an American socialite and member of the Kardashian family, last Wednesday.

Jenner’s tweet coincided with an immediate six-percent decrease in  the price of Snapchat’s stock (NYSE: SNAP),  erasing approximately $1.3 billion of the company’s market value. Analysts say there was no question the tweet sent the stock tumbling.

Jenner has not revealed any ownership of Snapchat securities, and there is no evidence that she does. However, if she had bet against Snapchat’s stock by buying put options ahead of her tweet, it may have been a form of market manipulation, experts say.

Put options give owners the right, but not the obligation, to sell a stock at a specified price in the future. Owners of put options are making a bet that the underlying security will decrease in price.

Some analysts said that if a celebrity were to profit by using their social media influence to alter a stock’s price, whether they could land in legal trouble could depend on several factors, including the intent of the post and the relationship between the celebrity and the company involved.

“If you take a financial position and you’re set to profit off that tweet, you would have to disclose that position,” said Jim Cox, a securities law professor at Duke University School of Law. “That’s true even if your statement expresses your actual belief about the security.”

Donald Langevoort, a professor at Georgetown Law School and expert in securities regulation law, said regulators would have to examine the motive behind any such post on social media.

“If the only reason this tweet is going out is to drive down the market price, then that’s a classic case of manipulation,” Langevoort said. “But it’s not always easy to prove, because people can have so many different motives.”

The Federal Trade Commission has rules which state that “celebrities, athletes and other influencers” on social media must make clear if they are receiving money from a product they advertise.

“If there is a ‘material connection’ between an endorser and an advertiser – in other words, a connection that might affect the weight or credibility that consumers give the endorsement – that connection should be clearly and conspicuously disclosed,” the FTC wrote in its guidance on endorsements.

However, in Jenner’s case, there was no known paid endorsement or deal between her and Snapchat or any competitor. Instead,  she just tweeted her opinion. As such, she would probably be in the clear, said Mitchell J. Katz, a public affairs specialist at the FTC.

When Whole Foods was taking over Wild Oats,   John Mackey, the CEO of Whole Foods, went online and created a fake personality, Katz said,  referencing a 2007 merger between the two organic food companies. “He was talking down Wild Oats to drive down the share price, and we didn’t bring any action against him because it wasn’t in our purview,” Katz said.

However, Katz noted that such cases—like the Jenner tweet—could have very different legal repercussions with the Securities and Exchange Commission than with the FTC, if Jenner did in fact own Snapchat shares or options.

The SEC declined to comment, but Cox pointed out similar securities cases in the past.

“There have been analysts who have taken out clips in the paper to promote a stock that they own and inflate its value,” said Cox. “Twitter is not a newspaper, but it’s the same idea. And the SEC took action against those analysts because it’s a form of manipulation.”

Overall, the analysts agreed that tweets such as Jenner’s likely wouldn’t face any scrutiny from regulators, given both Jenner’s lack of a fiduciary duty to Snapchat and her ostensibly honest motive for tweeting.

“Ultimately, if what you’re saying is true and you have no insider information that you’re precluded from taking advantage of, then it’s just your opinion,” said Langevoort. “And it’s very hard to turn that opinion into securities fraud.”

SNAP shares recovered their losses this week, and were trading at $17.32 per share by Wednesday’s closing bell.