Polymarket indicates an 83,7% chance of victory for Flávio Bolsonaro on the eve of the second round.

On the eve of the second round, Polymarket, the world's largest prediction market platform, gives Senator Flávio Bolsonaro (PL) an 83,7% probability of winning, compared to 17% for President Luiz Inácio Lula da Silva (PT), according to a quote verified by BNLData at 15:33 pm this Saturday (24). On the platform, the price of each contract works as the estimated probability: whoever buys "yes" for Flávio at 84 cents of a dollar receives US$ 1 if he wins.

The market for the Brazilian presidential election has accumulated US$195,1 million in trading volume since it opened on September 18, 2025. Settlement will be based on open data from the Superior Electoral Court. Historical data shows that Lula was the favorite among bettors for most of this period. The shift occurred on the eve of the first round and intensified after Flávio finished ahead in the polls.

The favoritism attributed by bettors contrasts with the polls. In the last Datafolha poll, released on Thursday (22), the candidates were tied with 50% of the valid votes each. Quaest on Wednesday (21) showed Flávio with 45% and Lula with 44%, a technical tie within the margin of two points. The two institutes will release the latest polls on Saturday night. In the first round, Flávio received 47,03% of the valid votes and Lula, 45,16%.

It's important to remember that Polymarket is not authorized by the Brazilian Securities and Exchange Commission (SPA/MF) and that Law 14.790/2023 limits fixed-odds betting in Brazil to sporting events and online games. Betting on elections is not part of the regulated Brazilian market.