Flávio Bolsonaro leads in predictions markets.
Flávio Bolsonaro (PL-RJ) leads the estimates of probability of victory in the October presidential elections on the digital forecasting platforms Kalshi and Polymarket. The percentages were released on Sunday afternoon (September 20th) and updated until the evening of the same day, according to CNN Brasil.
However, the data has important limitations. The platforms do not follow methodological criteria for electoral research, and the operation of this type of predictive market is prohibited in Brazil by a resolution of the CMN (National Monetary Council).
In the Kalshi poll, Flávio appears with a 59% probability of being elected president. The current president and candidate for re-election, Luiz Inácio Lula da Silva (PT), registers a 42% chance on the same platform. The other candidates appear with marginal percentages: Renan Santos, from Missão, has 0,8%, while Ronaldo Caiado (PSD) and Romeu Zema (Novo) each have less than 0,1%.
In the Polymarket poll, the numbers are similar. Flávio appears with a 58% chance of winning, and Lula with 42%. Among the others, Renan Santos registers 1%, and Caiado, Augusto Cury (Avante), and Zema are all below 1%.
What do these platforms measure?
Kalshi and Polymarket are international "prediction market" platforms where bettors trade with real money, usually in cryptocurrencies, on the probability of future events. In the case of elections, participants buy and sell contracts linked to political outcomes, and the prices of these assets vary according to demand.
In practice, the percentages displayed function as a collective estimate: the more users who buy a particular result, the higher its market value tends to be. The numbers do not reflect declared voting intention and do not follow criteria such as representative sampling of the population, unlike conventional electoral polls.
Prohibition in Brazil
In April, the CMN (National Monetary Council) approved a resolution prohibiting the offering and trading of bets linked to political, electoral, social, cultural, or entertainment issues in Brazil by predictive market platforms. The regulation governs the organization and operation of the derivatives market in the country.
The rule does not apply to conventional bets, which operate with a fixed prize payout if the bet is successful. In the model of platforms like Kalshi and Polymarket, operators sell "yes or no" type contracts, and the buyer receives a prize if the bet is successful. The resolution prevents these platforms from offering bets on elections, games, reality shows, and other events of a non-economic nature, at the discretion of the CVM (Securities and Exchange Commission).
