Michael Burry took a break from commenting on the stock market to focus his attention on booming prediction markets like Kalshi.

In short: not impressed.

The investor, made famous by Michael Lewis’ crisis-era saga “The Big Short,” shared his pessimistic assessment as prediction platforms withstand criticism over how ordinary users are faring and claims that prediction markets are no different than regular gambling.

Burry focused on the latter issue, arguing that betting on outcomes such as the weather or a sporting event is a game that has simply been enabled by a gray area in the rules.

“Kalshi, as with all prediction markets, finds itself in a regulatory vacuum within an extremely highly regulated and highly taxed industry that gambles no matter what you call it,” he wrote on X.

Kalshi fought claims made last week by a think tank that regular users have lost nearly $600 million on the site since 2018. The Roosevelt Institute claims a small group of professional traders have a clear advantage over regular users, leading to unbalanced profits and losses.

Burry also pointed to issues surrounding insider trading. Tarek Mansour, CEO of Kalshi, recently said that it is easier to catch insider trading users in prediction markets than in the stock market.

Burry doesn’t seem convinced.

“Kalshi presents the possibility of gambling and cheating, and the loophole allows it in all states,” he wrote. “Of course, it is number one by far and will continue to grow as long as society steps aside and allows these horrible, basic human weaknesses to overlook any and all logical, moral and decent challenges.”

Thomas Braziel, a distressed debt investor, recently made similar claims, highlighting the risk to investors that could arise from a lack of regulation in prediction markets, as well as the risks to platforms if regulation one day becomes stricter. Braziel described the prediction sites’ business model as “sleight of hand,” highlighting what he sees as an ongoing campaign to circumvent gambling laws.

Burry focused on how the current regulatory structure could put retail users at a disadvantage, similar to the case made by the Roosevelt Institute in its recent study.

“There is nothing to prevent cheating in prediction markets. Cheating, the only activity as old as gambling, has the same power to drive humans to extremes,” Burry added.