Polymarket Accuses Kalshi of Stealing Ideas and Searches for an Informant Inside Its Office

^{Pictured: Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour}

The New York Post reported that a dispute had emerged between two of the largest prediction market platforms, with Polymarket suspecting its main rival, Kalshi, of corporate espionage. According to the report, Polymarket has compiled an internal dossier, codenamed Copycat, documenting around a dozen alleged leaks of commercially sensitive information.

The suspicions intensified after two major incidents. In February, Kalshi held a free grocery promotion in New York shortly before a similar Polymarket event, which had been in preparation for several months.

“Their goal was simply to undermine our event. It was very important to Shayne [Polymarket’s founder], because he grew up in New York. We were disappointed,” an anonymous source told The New York Post.

In April, Polymarket was also preparing to announce the launch of perpetual futures trading. However, an hour before the announcement, a press report said Kalshi was launching a similar financial product.

One Polymarket executive said the dossier contained only a tenth of the instances in which the company believes Kalshi copied its rival.

As part of the investigation, Polymarket’s security team is examining whether there may be an informant inside the company.

The company also darkened the windows of its office in Manhattan’s SoHo district in the spring. The move was linked to the fact that the office of venture capital firm Paradigm, a key investor in Kalshi, is located directly across the street. Polymarket’s management suspected that employees’ screens may have been visible from across the street.

Kalshi and Paradigm representatives firmly denied all the allegations in comments to The New York Post. Kalshi described its rival’s suspicions as “delusional”, saying all its products and marketing campaigns are developed independently and well before any public announcements. Paradigm said its employees do not look into other companies’ windows, and that similarities in release schedules were the result of normal market competition within the same technology niche.