The Big Read · Brazil · Sunday 25 October 2026
Key Facts
—Runoff. Brazil votes today, Sunday 25 October 2026, between President Lula and Senator Flávio Bolsonaro.
—US voters. About 265,000 Brazilians are registered to vote in the US; only 28.45% voted in the first round.
—AI posts. Lupa counted 1,423 AI-made or AI-altered election posts among 1,486 suspect posts.
Brazil Election Data Room
Runoff poll average: Flávio Bolsonaro 51.0%, Lula 49.0%
45 national polls from 21 pollsters since 4 October, updated hourly. Every poll, free to download.
—Court fight. The Supreme Court gave the electoral court three hours to explain Indigenous voter transport rules.
—Prediction markets. Polymarket gives Flávio Bolsonaro 79.8% and Kalshi 81% to win (2:14 a.m. ET, 25 October).
—Power Index. Brazil ranks 1st of 14 in The Rio Times Latin America Power Index, with 75.0 points (October 2026 edition).
Prediction markets · who wins the runoff
Implied chance of winning Brazil’s presidency on 25 October, from traders’ prices.
Polymarket
Flávio Bolsonaro 79.8% · Lula 19.5% (US$197 million traded)
Kalshi (regulated in the US by the CFTC)
Flávio Bolsonaro 81% · Lula 19%
As of 25 October, 2:20 am ET (06:20 Lisbon), updated every 20 minutes. Prices are bets, not polls, and can move fast.
Why we show this: prediction markets turn real-money bets into a live probability that moves within minutes of the news, which is why investors, campaigns and newsrooms in the United States now follow them closely. We show them next to polls and official results, never instead of them.
Brazil’s presidential runoff is today, and the polls, the betting markets and the courts are telling different stories about how it will end.
In Plain English
- Runoff: A second round held when no candidate wins more than half of valid votes in the first round.
- Flávio Bolsonaro: A conservative senator from Rio de Janeiro and son of former president Jair Bolsonaro.
- Lula: Luiz Inácio Lula da Silva, the sitting president and Workers’ Party candidate.
- Prediction market: An online platform where traders buy contracts that pay if an event happens.
Brazil Votes Today, With 265,000 Voters in the US
Brazil holds its presidential runoff today, Sunday 25 October 2026, between President Luiz Inácio Lula da Silva and Senator Flávio Bolsonaro, son of former president Jair Bolsonaro. The first round was on 4 October.
The Superior Electoral Court (TSE), Brazil’s election authority, lists about 265,000 registered voters in the United States. Boston, Miami and New York have the most.
The United States holds roughly 29% of the about 917,000 Brazilians registered abroad.
Voters abroad can vote only for president. Turnout is the open question: 71.55% of US-registered voters stayed home in the first round.
Markets Back Flávio While Polls Show a Tie
Final polls describe a close race. Quaest, published on 21 October, had Flávio at 45% and Lula at 44% of total votes.
Datafolha, which interviewed 2,520 voters from 20 to 22 October, had the two candidates level at 50% each of valid votes. Valid votes exclude blank and spoiled ballots.
Betting prices favour Flávio far more than the polls do. Polymarket shows him at about 80% early today.
Brazil’s National Monetary Council banned betting contracts on events such as elections from 4 May 2026, and the government ordered Polymarket and Kalshi blocked, with the telecoms regulator Anatel carrying it out.
What Prediction Markets Say
On Polymarket, Flávio Bolsonaro trades at 79.8% and Lula at 19.5% to win the presidency, with about US$197 million traded. On Kalshi, a platform regulated in the US by the CFTC, the prices are 81% for Flávio and 19% for Lula (2:14 a.m. ET, 25 October).
These prices are real-money bets, not polls, and they sit well above the near-even split in the surveys. Why we show this: prediction markets turn real-money bets into a live probability that moves within minutes of the news, which is why investors, campaigns and newsrooms in the United States now follow them closely. We show them next to polls and official results, never instead of them.
AI Posts Reach the Campaign’s Final Days
Lupa, a Brazilian fact-checking agency, runs a live tracker called VigIA. It counted 1,423 election posts made or altered with artificial intelligence between 16 August and 22 October, out of 1,486 suspect posts it analysed.
Lupa published the latest count on 24 October, with data to 22 October. Deepfakes are fake images, video or audio that show real people doing or saying things they never did.
Court Fight Over Indigenous Voter Transport
On Saturday 24 October, Supreme Federal Court president Edson Fachin gave the TSE three hours to explain its rules for transporting Indigenous voters. His order asked only for information.
On Friday 23 October, TSE president Kássio Nunes Marques had required each federal Indigenous-voter transport operation to get prior approval from an electoral judge. Prosecutor General Paulo Gonet then asked the Supreme Court to step in, warning that voters who must travel for hours or days might be unable to reach their polling stations.
No ruling on Gonet’s request had been reported by Saturday 24 October.
What Links These Stories
All four reports ask the same question: how many people can vote, and how will the result be read? The US vote, the Indigenous transport rules and the AI posts touch who votes and what voters see, while the betting prices show how confident traders are.
These are separate stories with one setting, a runoff too close for the polls to call.
What It Means for US Readers
US investors with Brazilian exposure will see the first market reaction when trading resumes on Monday 26 October.
About 265,000 Brazilians registered in the United States can vote, so the count abroad is also a US story. The winner will set the tone for Brazil’s relations with Washington.
What to Watch Next
Watch the first official count from the TSE after polls close in Brazil, and whether the betting prices move toward the polls or away from them. Watch also whether the Supreme Court rules on the Indigenous transport request.
What Is Not Known
Final turnout is not known; the only benchmark abroad is the 28.45% of the first round. We found no figure for how many Indigenous voters the transport rules affect.
The effect of AI posts on votes is not known. Market prices are bets and can move sharply.
Sources
Superior Electoral Court (TSE) · Polymarket · Kalshi · The Rio Times · The Rio Times · The Rio Times · The Rio Times
This article was produced by The Rio Times’ automated newsroom system. How we use AI · Report an error · Editorial responsibility: Matthias Camenzind, Editor-in-Chief
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Frequently Asked Questions
How many Brazilians in the US can vote?
Brazil’s electoral court lists about 265,000 registered voters in the United States. Voters abroad can vote only for president.
Why do betting prices differ from polls?
Prices reflect traders’ real-money bets, not surveys of voters. Traders may weigh small poll leads more heavily, or they may simply be wrong.
What did the Supreme Court order on Indigenous voters?
It gave the electoral court three hours to explain its transport rules. Its order asked only for information, and no ruling on the prosecutor’s request had been reported by Saturday 24 October.
How many AI election posts did Lupa find?
Lupa’s tracker counted 1,423 election posts made or altered with AI between 16 August and 22 October, out of 1,486 suspect posts analysed.
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