On Sunday, October 25, Brazil will decide its next president in a high-stakes second-round runoff featuring two radically opposing visions for the country: Flávio Bolsonaro, a conservative aligned with Donald Trump’s political playbook, or incumbent President Luiz Inácio Lula da Silva, a champion of multilateralism and Global South sovereignty.
Following the October 4 first round—where both traditional polling and prediction markets failed to project the winner—this market continues to present high-value opportunities for traders. Here is an updated breakdown comparing what the latest polls and prediction market odds reveal heading into election day.
The Case for Flávio Bolsonaro: Prediction Markets Point to a Clear Lead
Flávio Bolsonaro, a senator and son of former President Jair Bolsonaro, pulled off an upset in the first round by taking top spot with 47.03% of the vote. Lula, the incumbent, finished behind expectations at 45.16%.
As a result, the Liberal Party (PL) candidate has emerged as the heavy favorite on major prediction platforms, trading at 79% odds on Kalshi and 78% on Polymarket. Beyond holding a narrower path to clear the 50%+1 threshold needed to secure the presidency for the 2027–2031 term, Bolsonaro holds a distinct advantage in consolidating support from eliminated candidates.
The conservative senator enters the runoff with endorsements from nearly every right-wing and center-right party in Brazil. If he successfully absorbs these voting blocs, he will comfortably cross the majority threshold required for victory on Sunday night.
The Case for Lula: Can Post-Election Stimulus Shift the Odds?
Contracts backing a victory for the incumbent president plummeted in the immediate aftermath of the first round, dropping from around 41 cents to 12 cents on major prediction exchanges. However, Lula's odds have seen a modest recovery in recent days, driven primarily by two major factors.
Following the first round, Lula announced a wave of targeted policy initiatives—including fuel subsidies, direct cash transfers for low-income households, and debt relief for small-business owners—aimed directly at winning over undecided voters.
At the same time, the president retains a massive pool of potential voters to mobilize. Over 33 million citizens abstained in the first round, representing a 21.08% voter turnout drop, the highest abstention rate since 1998. Winning over even a fraction of these disengaged voters could shift the electoral trajectory back in his favor.
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Polls vs. Odds: Statistical Tie Creates a Widening Gap
In contrast to the steep favorite status indicated by prediction markets, traditional opinion polls present a tight contest:
- Quaest: Released on October 21 following a heated televised debate, Quaest places Bolsonaro at 45% and Lula at 44%—a single-point margin well within the statistical error.
- Nexus: Published on October 19 (conducted prior to the presidential debate), Nexus shows Bolsonaro leading by less than a point, 46.5% to 45.9%.
- Datafolha: Released on October 15, Datafolha projects Bolsonaro at 47% voter intention compared to Lula’s 45%.
| Flávio Bolsonaro | Lula da Silva | |
|---|---|---|
| Kalshi | 79% | 22% |
| Polymarket | 78% | 25% |
| Quaest (10/21) | 45% | 44% |
| Nexus (10/19) | 46.5% | 45.9% |
| Datafolha (10/15) | 47% | 45% |
