The probability of Elon Musk winning his lawsuit against OpenAI, as tracked by the prediction market Kalshi, has declined following his testimony in a federal court in Oakland. The odds, which traders had placed at 60% when the trial began, dropped to a low of 34% after Musk’s appearance and stood at 40% as of Wednesday afternoon.
The lawsuit, which went to trial on April 27, centers on claims made by Musk against OpenAI, the artificial intelligence company he co-founded in 2015. According to data from Kalshi, the contract related to the lawsuit’s outcome has a trading volume of over $890,000.
The shift in market sentiment coincided with Musk’s three-day testimony, which concluded on April 30. During his testimony, Musk accused OpenAI CEO Sam Altman and President Greg Brockman of deviating from the company’s original nonprofit mission. He stated, “I came up with the idea, the name, recruited the key people, taught them everything I know, provided all the initial funding.”
Under cross-examination by OpenAI’s lead counsel, William Savitt, Musk described some questions as being “designed to trick” him.
Eric Zitzewitz, a professor of economics at Dartmouth College, commented on the movement in the prediction market. He suggested that the “market reacted” to news coverage of the trial proceedings.
The basis of Musk’s lawsuit includes the claim that his initial funding of approximately $38 million was intended for a nonprofit entity and was later used for commercial purposes. Musk left OpenAI’s board in 2018. The company established a for-profit subsidiary in 2019. In a post on the social media platform X, OpenAI called Musk’s case “baseless.”
The trial also included a filing that showed Musk had sent a text message to Brockman regarding a potential settlement days before the trial commenced.
The lawsuit is one of more than 150 contracts related to Musk and his companies available for trading on Kalshi. Zitzewitz noted that events with a clear timeline often attract high trading volume. “People like to trade things close to being resolved,” he said.
