Portugal Blocks Polymarket After €4M Election Betting Surge

Posted on: January 20, 2026, 06:47h. 

Last updated on: January 20, 2026, 06:47h.

Philip Conneller @casinoorgphilc Read More
Expertise: Gaming Business, Regulation, Tribal Gaming.
  • Seguro leads first round; Ventura second; Portugal heads to runoff
  • Polymarket odds on Seguro surged before results, raising leak concerns
  • SRIJ says Polymarket is illegal locally and ordered it to stop

Portugal has become the latest jurisdiction to order Polymarket to cease and desist. The prediction market, which had previously flown under the radar in the country, became a conspicuously hot topic after heavy trading in the hours before the results of its general election were announced Sunday.

Polymarket, Portugal SRIJ, prediction markets, Portuguese presidential election, election betting
Socialist Party candidate António José Seguro, center, is celebrated by supporters during a rally in Lisbon on January 16, 2026, on the eve of Portugal’s general election. But a sudden surge of eleventh-hour betting on Polymarket has raised eyebrows in the country. (Image: Patricia De Melo Moreira/AFP/Getty Images)

More than €4 million ($4.3 million) was wagered on Polymarket’s presidential markets during that short window, Portuguese broadcaster Renascença reported, leading to concerns that wagers may have been informed by leaked exit polls or other non-public information.

Ultimately, opposition Socialist Party candidate António José Seguro led the vote with 31%, ahead of far-right Chega candidate André Ventura, who placed second with 24%. However, neither secured the 50% required to win outright.

As a result, the election will proceed to a second round, or “run-off,” in which only the top two finishers are eligible to stand.

Sudden Surge for Seguro

On election day, Seguro’s implied probability on Polymarket began at around 60% early in the afternoon. By about 6 p.m., roughly one hour before polls closed, his odds had climbed to approximately 95%. After exit-poll projections circulated, but before official results were released, those odds approached 100% certainty on the platform.

There is currently no evidence of insider trading. Exit-poll projections began circulating around the same time as the odds swing, suggesting the market was simply doing what markets do: rapidly digesting new information. Whether that information was appropriately shared is a separate question for Portuguese authorities.

Portugal’s gambling regulator, SRIJ, confirmed it ordered the crypto-based platform to halt operations because it is illegal under national rules that limit online gambling to licensed sports betting, casino-style games, and horse racing — not political event markets. The regulator acknowledged it had only recently become aware of Polymarket’s activity.

Prediction Market Scrutiny

Portugal joins a growing list of jurisdictions scrutinizing political prediction markets that operate outside traditional gambling and financial frameworks. Polymarket has faced regulatory action elsewhere, including in the US, where it reached a 2022 settlement with the Commodity Futures Trading Commission (CFTC) over unregistered event-based contracts and agreed to block US users.

Ahead of the most recent US presidential election, the CFTC also sued rival platform Kalshi, seeking to bar it from offering election outcome contracts on the grounds that such markets violate US commodities law. A federal court declined to grant the requested relief.

Polymarket and Kalshi argue their election markets provide useful signals for forecasting political outcomes and hedging political risk. Critics counter that the products amount to gambling under a different name and warn they could undermine confidence in the electoral process.