10x profit if a US-Iran ceasefire holds…Polymarket sees another wave of bets suspected of insider trading

Large sums of money are pouring into prediction-market contracts betting on the possibility of a ceasefire between the United States and Iran, fueling suspicions of insider trading.

According to The Guardian, a UK daily, on March 23 (local time), Polymarket—a prediction betting site—has recently seen concentrated wagers worth hundreds of thousands of dollars on a contract asking whether a US-Iran ceasefire will be reached by March 31.

In particular, eight newly created accounts, apparently set up around March 21, each placed $70,000 (about 100 million won) on the outcome that a ceasefire will be reached. If a ceasefire is achieved by the 31st, the profit these accounts would earn would amount to $820,000 (about 1.22 billion won). Most of the new accounts appear to have been created late last week.

Experts suggest it is possible that an investor with inside information about the Iran war created multiple accounts to conceal their identity before placing bets.

Platform developer Ben York said, “If someone is trying to spread funds across accounts and hide their identity, it’s either a large investor seeking to reduce market impact, or it’s highly likely to be insider trading.”

However, determining whether the owners of these accounts are actually insiders is virtually impossible, the report said. Polymarket accounts are anonymous, and bets are placed in cryptocurrency, making it difficult to track the true owners.

Previously, Polymarket also drew attention when a user wagered $34,000 (about 50 million won) on a bet that “the US will invade Venezuela by January.”

Because the user placed a large bet shortly before the US arrested President Nicolás Maduro, suspicions were raised that the person had inside information from the Donald Trump administration.

In response, Polymarket revised its rules to bar users from trading such contracts if they possess non-public information or could influence the outcome.

Kalshi, another prediction betting site, also decided to prohibit political candidates from trading contracts related to their own elections and to preemptively block athletes and related personnel from betting on sports-related contracts.

These moves are seen as reflecting growing regulatory scrutiny from US politicians toward the industry. On the day, Senators Adam Schiff (D-California) and John Curtis (R-Utah) introduced a bill to ban betting on sports-related contracts via prediction betting sites.

If the bill passes, analysts say it could negatively affect the business outlook for prediction betting sites such as Polymarket.

Ko Jeong-sam, Hankyung.com reporter jsk@hankyung.com