Flávio Bolsonaro wins the second round of the 2026 Brazilian presidential election by at least 12 percentage points.
Brazil's 2026 presidential runoff takes place in late October. This resolves as true if Flávio Bolsonaro defeats his opponent by a margin of 12% or greater among valid votes.
Across 6 frontier models answering independently, the panel has all but ruled it out: the median is 4%.
They broadly agree, 11 points between Grok at 12% and Claude at 1%.
Money disagrees. The market sits at 0%, so the models are 4 points more confident than people with cash on the outcome.
Nothing is settled until 26 Oct 2026, when the outcome is checked against sources and every number above gets a permanent score.
- AI edge
- +4 pts
- Moved this week
- -3 pts
- Since we asked
- -3 pts
- Volume
- $1.4M
The models are slightly more confident than traders risking real money: 4% against 0%.
What each one said
-
GrokxAI
First-round result plus late polls must already show Flávio with a double-digit lead that holds through 25 Oct.
- First round was 4 Oct; only if Flávio advanced and Datafolha/Ipec now put him ≥56-44 does a 12-pp win remain plausible.
- Polarized runoffs since 2014 have finished 2–10 pp; 12 pp last occurred in 2006, well above the recent base rate.
- Nine days left, TSE rules and campaigning frozen, so only a late scandal or turnout collapse would move the number.
12% -
GPTOpenAI
A double-digit runoff requires both a Bolsonaro victory and an unusually lopsided national mandate in nine days.
- Flávio must first make the October 25 runoff competitive; a 12-point valid-vote margin implies roughly 56–44 or wider.
- Brazil’s recent presidential runoffs were close: Lula beat Bolsonaro 50.9–49.1 in 2022, while 2018’s 55.1–44.9 is the key precedent.
- A credible October poll average showing Flávio above 55% against his named runoff opponent would sharply raise this estimate.
4% -
QwenAlibaba
Flávio likely isn't even in the runoff, and a 12-point margin in a Brazilian second round is historically rare.
- Tarcísio de Freitas was widely favored as the Bolsonaro-aligned candidate over Flávio, who carries the rachadinha scandal and lower name-brand appeal.
- Only three Brazilian runoffs since 1989 produced margins ≥12pp (2002, 2006, 2010), all involving Lula at peak popularity.
- Even if Flávio somehow made the runoff, polling 9 days out would need to show a landslide trajectory; a development that would change this is a major scandal eliminating…
4% -
DeepSeekDeepSeek
A 12-point runoff blowout requires Flávio to be a dominant favorite, and no credible polling shows him anywhere near that.
- Brazilian presidential runoffs since 1989 have almost all landed under 10 points; Lula beat Bolsonaro by 1.8 in 2022 and Cardoso won by 27 in 1994.
- Flávio polls well behind Lula and behind several right-wing rivals in first-round scenarios, so reaching a runoff at all is not assured.
- Even a favorable late swing would need to move 10+ points in nine days, which no modern Brazilian runoff has done.
3% -
GeminiGoogle
Flávio Bolsonaro is unlikely to be the nominee, and Brazil's polarized electorate precludes a 12-point runoff landslide.
- Tarcísio de Freitas is the favored right-wing standard-bearer over Flávio, who faces high personal negatives and investigations.
- Recent Brazilian runoffs are fiercely contested, with Bolsonaro's 2018 win being 10.7 points and Lula's 2022 margin just 1.8 points.
- A 56-44 blowout by Flávio against Lula or any mainstream candidate requires an unprecedented total collapse of the left.
2% -
ClaudeAnthropic
Flávio Bolsonaro isn't even confirmed as a candidate, let alone a runoff winner by a 12-point margin.
- Flávio Bolsonaro has not been the frontrunner or confirmed presidential candidate in 2026 polling or nominations.
- Brazilian runoffs are typically competitive (single-digit margins), making a 12+ point blowout rare historically.
- Would need major shift: his candidacy confirmed, making the runoff, and a landslide win—none of which current signals support.
1%
6 of 6 models answered · 11 points between the highest and lowest. None was shown the market price.
Resolution criteria
The second round of the presidential election is scheduled to take place in Brazil on October 25, 2026. This market will resolve according to the margin of victory between the top two candidates in the second round of the next Brazil Presidential Election. For the purpose of this market, the “margin of victory” is defined as the absolute difference between the percentages of valid votes received by the first- and second-place candidates. Percentages of the valid votes received by each candidate will be determined by dividing the total number of valid votes each of the top two candidates receives by the sum of all valid votes cast in the election. If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket. If a candidate other than Flávio Bolsonaro or Luiz Inácio Lula da Silva receives the most valid votes in the second round, or if the top two candidates receive exactly the same number of valid votes, this market will resolve to "Other". This market will resolve based on the official vote count once the vote count has been made official. If a recount is initiated before the vote total has been made official, the market
Question sourced from Polymarket on 16 Oct 2026. Forecast by google/gemini-3.8-flash, anthropic/claude-sonnet-5, openai/gpt-5.6-terra, x-ai/grok-4.6, deepseek/deepseek-v4.1-flash, qwen/qwen3.8-max-0902 via OpenRouter.