Polymarket and Kalshi both priced Bolsonaro as a heavy favorite hours before Brazil's count. The contracts began sliding after a court extended voting and collapsed as results came in. Lula won by about 4.4 million votes, and Bolsonaro says he will seek an annulment.
At 1:47 p.m. Eastern on Sunday, Polymarket's contract on whether Flávio Bolsonaro would win Brazil's presidency traded at 81.4 cents. Kalshi's equivalent traded at 82 cents. By 11 p.m., Polymarket's was at 0.05 cents.
Brazil's electoral court declared President Luiz Inácio Lula da Silva reelected at 8:08 p.m. Eastern, with 97.69% of ballots counted. Final figures gave Lula 64,256,232 votes, or 51.79% of valid votes, against 59,826,041, or 48.21%, for Bolsonaro.
How the price fell
The decline began before the polls closed, and the timing is precise.
At 2:46 p.m. Eastern, Lula's coalition asked the Supreme Court to extend voting hours. Justice Cristiano Zanin ordered a two-hour extension, to 7 p.m. Brasília time, at about 4 p.m. Eastern. Polymarket's Bolsonaro contract was at 77.35 cents at 3 p.m. and 75.85 cents at 4 p.m.
The electoral court began releasing partial results at about 4:45 p.m., while some polling stations were still open. The contract fell to 66.35 cents at 5 p.m. and 60.55 cents at 6 p.m., when the extended voting ended. The steepest drop came in the next hour, to 22.35 cents by 7 p.m., as the count turned toward Lula.
On Kalshi, Bolsonaro's contract was trading between 0.1 and 1 cent from 8:02 p.m., with about 3.37 million contracts changing hands in 36 minutes. On Polymarket, about $19.8 million traded in 24 hours, out of $44.7 million over the life of the market.
The moves followed the extension and the count. The prices alone do not show which traders sold or why.
What 82 cents meant
An 82-cent price is not a statement that Bolsonaro would win. It implies roughly an 18% chance that he would lose, and that outcome happened. What stands out is how far both venues sat from the polls, which had the race at 51% to 49% for Bolsonaro, within the margin of error. The markets had leaned on the first round, when Bolsonaro outperformed his polling.
The annulment question
Bolsonaro has not conceded. "It is impossible to recognize the result of these elections. I will ask for annulment," he said, targeting Zanin's extension. Both campaigns had sought extensions during the day. Analysts have said the margin makes a successful challenge unlikely, and the electoral court held an emergency meeting to review the extension's effect.
For traders, the question is settlement. Polymarket's contract resolves to the candidate who wins the election, and names the electoral court as the arbiter in cases of ambiguity. Kalshi's rules say its market "will close and expire after a winner is announced." Neither platform had posted a final settlement by early Monday.
Two readings
One reading is that the markets worked as designed: they priced the information available, then repriced within hours as the count arrived, with heavy volume confirming the move.
The other is that two large venues converging on the same favorite in a race the polls called a tie shows how much a prior surprise can anchor traders. The first-round result was treated as more informative than every poll that followed.
What to watch
Settlement of both contracts, any formal challenge filed with the electoral court and its response, and the opening of Brazilian markets on Monday.