Regulator moves against polymarket portugal as election betting spike triggers scrutiny

Hours before the Portuguese presidential results were announced, the platform polymarket portugal saw millions in bets, prompting urgent action from the national gaming regulator.

Portuguese regulator orders Polymarket to shut down

The Serviço de Regulação e Inspeção de Jogos (SRIJ) has ordered the online betting platform Polymarket, considered illegal in Portugal, to cease operations and be blocked in the country. However, the site remains accessible days after the initial order.

The regulator confirmed it had only become aware of Polymarket very recently, despite the platform having hosted highly liquid markets on the Portuguese presidential election. Moreover, SRIJ classified its activity as illegal under current national rules governing online gambling.

According to SRIJ, the site “has no authorization to offer bets in Portugal,” and national law bans wagers on political events or occurrences, whether domestic or international. That said, the platform continued to operate, including during the January presidential vote.

Order to block the site and uncertainty for bettors

The authority notified Polymarket on Friday to halt its activity in Portugal within 48 hours. Yet, by Monday, the site still appeared fully operational. As a result, SRIJ is now expected to instruct network service providers to block access to the platform at the infrastructure level.

Regarding the funds of Portuguese users, the regulator stressed that it only “regulates and inspects” companies formally licensed for online betting in Portugal. Moreover, SRIJ underlined that its legal power is limited to “notifying operators to voluntarily cease activity in Portugal.”

This means there is no guarantee that Portuguese bettors will recover their money once the site is blocked. In other words, users who placed bets on Polymarket do so without the protections that apply to authorized platforms.

Election markets and suspicions of insider trading

One of the most active segments on Polymarket was the presidential market, where more than €4 million moved in the hours before results were officially known. The intense late trading raised concerns about insider trading in betting and the potential misuse of early exit-poll data.

On election Sunday, António José Seguro started the day with a 60% implied probability of winning on the platform. By contrast, André Ventura had roughly a 30% chance of topping the vote according to the same market.

By 18:00, just one hour before polling stations closed, Seguro’s probability surged to 95%. Moreover, it quickly reached 100% as soon as projections showing his victory began to circulate publicly.

Rapid repricing in the presidential outcome markets

A similar pattern emerged in the market predicting who would become the next President of the Republic. At 18:30, António José Seguro had a 68.6% probability of reaching Belém. Within an hour, by 19:30, that figure jumped to 93.2%.

Over the same time frame, João Cotrim de Figueiredo saw his chances fall sharply. His probability of becoming President dropped from 22% to just 2.5%. By 20:00, when the first official results were released, Seguro’s probability was already back at 95%, reinforcing the impression that the market had settled on the winner ahead of time.

In the two hours between the moment Seguro’s odds began to spike and the release of early results, more than €5 million changed hands across several markets on Polymarket. Furthermore, analysis of on-platform data shows how quickly traders adjusted their positions once new information started to circulate.

Exit polls and the information gap

Overall, trading volume on the main presidential market has now exceeded $120 million, equivalent to about €103 million. Other related or alternative markets have accumulated nearly $10 million in wagers, around €8.1 million, confirming how important the election became for the platform.

The crucial question is how so many participants backed the eventual winner almost two hours before official results and one hour before the first televised projections. According to available information, the explanation lies in exit poll data that began circulating privately in the early evening.

Around 18:00, initial exit-poll projections started to move among media professionals and polling firms. These early numbers, still considered interim, already pointed to a comfortable victory for António José Seguro with more than 30% of the vote, significantly ahead of his rivals.

The broadcaster that investigated the case received these projections around the same time. They were shared by the polling companies involved and by television journalists preparing the coverage that would air at 20:00. However, the projections were only formally published at 20:00, by which time prediction markets had already reacted.

By the moment the first official projections went on air, trading on election-related contracts appeared to have largely converged on the final outcome. That said, the gap between the private circulation of data and its public release raises difficult questions about fairness and regulatory oversight.

How the Polymarket platform operates

The cryptocurrency-based prediction platform was launched in 2020 by Shayne Coplan and is currently valued at around $9 billion, approximately €7.7 billion. It allows users worldwide to speculate on future events across politics, sports, economics and culture.

The mechanism is straightforward: for each listed event, traders can buy or sell “yes” or “no” shares tied to a specific outcome. Each share trades between $0 and $1, reflecting the market’s assessment of the probability that the outcome will occur.

The sum of the prices of the “yes” and “no” shares is always equal to $1. Moreover, the lower the market-implied probability of success for a given candidate or scenario, the higher the potential payoff if the bet proves correct, but also the greater the risk of a total loss.

Trading mechanics and tax treatment

As with a traditional stock exchange, participants can trade their positions up until the outcome of the event is officially known. In the Portuguese presidential race, users could buy or sell contracts on each candidate until the moment the next President of the Republic was formally confirmed.

All transactions are processed on blockchain infrastructure, which, according to the project, helps to reduce costs and settlement times. Additionally, the platform uses the USDC stablecoin, a cryptocurrency pegged to the US dollar, as its base unit for deposits, trades and payouts.

Like other cryptocurrency assets, profits earned by users are subject to a 28% tax rate under the applicable fiscal framework. This adds another layer of complexity for Portuguese users, who may face both regulatory risk and tax obligations when interacting with an illegal betting site portugal.

Regulation, cross-border platforms and open questions

The SRIJ’s enforcement action highlights the broader challenge of blocking foreign betting platforms that operate online and rely on decentralized technologies. Even with orders to internet service providers, access can be difficult to contain, especially for users familiar with technical workarounds.

Moreover, the case illustrates a key dilemma for lawmakers: how to address cryptocurrency prediction markets regulation when platforms are based abroad, settle trades with stablecoins and tap into global liquidity. National regulators often find themselves reacting after the fact, when volumes and user exposure are already significant.

In this context, polymarket portugal has become a test case for how far domestic authorities can go in enforcing their rules on offshore platforms. The controversy around suspected exit poll data leak and potential unfair advantages for better-informed traders will likely fuel pressure for clearer standards and tighter international cooperation.

Ultimately, the presidential election episode shows how fast-moving blockchain-based markets can outpace traditional regulatory timelines. It also leaves unanswered questions for Portuguese users about the safety of their funds and the long-term future of politically themed crypto prediction markets.