Around 5:20 p.m. GMT, the title gained 8.10%, to 36.82 dollars.

Asked by AFP, the founder of Hindenburg Research, Nathan Anderson, confirmed that his company had taken a "significant" stake in Twitter, but below the 5% threshold, from which an investor must report to the market regulator (SEC).

Mr. Anderson said this was a first for Hindenburg, which had never before made a public statement of a long position, the company being rather known for its low bets on several titles.

For the financier, Twitter has a "solid case" in its legal proceedings, which began on Tuesday in a court in Delaware (eastern United States), which aims to force Elon Musk to respect his commitment to buy the social network.

The leaders of the platform accuse the versatile entrepreneur of having given up on this acquisition for fallacious reasons.

Elon Musk has thus argued that Twitter had minimized the number of spam messages on the network and had not provided him with enough data regarding inauthentic accounts, which the company disputes.

"The subject of bots", these automated accounts not maintained by an individual user, "is perhaps the worst excuse that Musk could have chosen to stop this transaction, knowing that this was clearly the reason why he was committed initially,” according to Mr. Anderson.

A few days after making a takeover offer, in mid-April, the man who heads the manufacturer Tesla had thus assured that if the acquisition was finalized, he would "defeat the spams" or fight against them "to the end".

For Nathan Anderson, Twitter has "more leverage" than its opponent in this procedure, "knowing the potential threat to the Musk empire in the event of a clear victory" of the social network.

"The market views this lawsuit as 'very strong'," Wedbush Securities analyst Dan Ives said in a note.

"The action now incorporates a significant likelihood that Musk will ultimately have to agree to pay significantly more than $1 billion '--the severance pay provided for in the contractor's original agreement with Twitter--" and even the possibility that he will have to buy the company at the expected price," explained the analyst.

© 2022 AFP