Brazil's 2026 election: what prediction markets say

Brazil votes on Sunday 4 October 2026, with a runoff on 25 October if no presidential candidate passes half the valid votes. As of 4 September 2026, Polymarket priced Luiz Inácio Lula da Silva at 55.5 cents to win the presidency and Flávio Bolsonaro at 41 cents, on 142.9 million dollars of traded volume. The polls have the runoff closer than that.

Prices last checked: 4 September 2026.

What do the markets say today?

The market treats a Lula versus Flávio Bolsonaro runoff as close to certain and the winner of that runoff as genuinely open. Both candidates are priced above 96 cents to reach the second round, and an outright first round win by anyone is priced at 5 cents.

Market (Polymarket)	Contract	Price, 4 September 2026	Event volume, USD
Brazil Presidential Election (winner, including runoff)	Luiz Inácio Lula da Silva	55.5 cents	142,895,649
Brazil Presidential Election (winner, including runoff)	Flávio Bolsonaro	41.0 cents	142,895,649
Brazil Presidential Election (winner, including runoff)	Renan Santos	1.8 cents	142,895,649
Brazil Presidential Election (winner, including runoff)	Augusto Cury	1.3 cents	142,895,649
Which candidates will advance to the runoff?	Lula	98.1 cents	572,120
Which candidates will advance to the runoff?	Flávio Bolsonaro	96.5 cents	572,120
Will any candidate win outright in the first round?	Yes	5.0 cents	214,555
First round, second place	Flávio Bolsonaro	83.5 cents	6,304,439
Chamber of Deputies, most seats	PL	56.5 cents	103,030
Senate seats contested in 2026, most won	PL	82.5 cents	296,707

Prices and volumes were read from the Polymarket Gamma API on 4 September 2026 (presidential, runoff qualifiers, first round outright). A price in cents is a probability: 55.5 cents means the market treats the outcome as 55.5 percent likely.

The size is worth stating plainly. At 142.9 million dollars, the Brazilian presidential market has more than ten times the volume of the Polymarket balance of power market on the US midterms, which stood at 11.0 million dollars on the same day. Almost none of that money is Brazilian, for reasons covered further down this page.

What does the price say about the first round on 4 October?

The market expects a runoff. The contract on any candidate winning outright in the first round, which in Brazil requires more than half the valid votes, traded at 5 cents on 4 September 2026. The first round second place market has Flávio Bolsonaro at 83.5 cents and Lula at 12.7 cents, which is the market saying it expects Lula to finish first on 4 October and Flávio Bolsonaro to finish second.

The first round margin market is where the disagreement lives. On 4 September 2026 Polymarket priced Lula winning the first round by less than 5 points at 44 cents and by 5 to 10 points at 38.5 cents, with Flávio Bolsonaro leading the first round by less than 5 points at 6.1 cents. Roughly 83 cents of that market sits inside a 10 point Lula lead, and all three polls below put the first round gap inside that band, so on the first round the market and the pollsters broadly agree.

Parties filed 13 presidential registration requests before the 15 August deadline, one more than the 12 filed in 2022 (Senado Notícias, 17 August 2026). Only four of them are priced above one cent to win.

What does the price say about the runoff on 25 October?

The runoff price moved harder in August than in the previous six months. The Lula contract traded at 64.5 cents on 1 August 2026, then 55.5 cents on 1 September and 55.5 cents on 4 September. Over the same weeks Flávio Bolsonaro went from 24.3 cents on 1 August to 39.3 cents on 1 September and 41 cents on 4 September, according to the price history behind the presidential market. A 17 point swing in five weeks is a large move in a market this deep.

Flávio Bolsonaro is the Liberal Party candidate, running with the endorsement of his father, former president Jair Bolsonaro, who announced the succession in December 2025 (Al Jazeera, 6 December 2025). Lula is running for a fourth term with Geraldo Alckmin again as his running mate.

Below the presidency, the market is much more confident about Congress than about the executive. PL is priced at 82.5 cents to win the most contested Senate seats and 56.5 cents to hold the most seats in the Chamber of Deputies. A president from one camp with a legislature from the other is the outcome the market considers most likely, and it is not a scenario most poll coverage prices at all.

Prediction market or opinion poll: which is closer?

They currently disagree by a few points on the runoff, and the polls are tighter than the market. Three registered polls published in the ten days to 3 September 2026:

• Genial/Quaest, fieldwork 30 August to 1 September, 2,004 voters, margin of error 2 points, registration BR-07065/2026: first round Lula 37 percent, Flávio Bolsonaro 29 percent, Augusto Cury 10 percent; runoff Lula 42 percent, Flávio Bolsonaro 41 percent (Poder360, 2 September 2026).
• Datafolha, fieldwork 1 to 3 September, 2,002 respondents, margin of error 2 points, registration BR-03669/2026: first round Lula 39 percent, Flávio Bolsonaro 32 percent; runoff Lula 46 percent, Flávio Bolsonaro 44 percent (Gazeta do Povo, 3 September 2026).
• AtlasIntel, fieldwork 25 to 30 August, 5,014 respondents, margin of error 1 point: first round Lula 43.4 percent, Flávio Bolsonaro 33.7 percent; runoff Lula 47.1 percent, Flávio Bolsonaro 42.6 percent (Gazeta do Povo, 31 August 2026).

Two of the three runoff readings are inside the margin of error. The market at 55.5 against 41 is a wider gap than any of them. Someone is wrong, and on 25 October the answer becomes public.

Brazilian polls carry an unusual advantage for a forecaster: they are legally registered. Article 33 of Lei 9.504/1997 requires firms to file the client, the cost and funding source, the methodology, the fieldwork period, the sampling plan, the confidence interval and the margin of error with the Electoral Court, up to five days before publication. That is why every serious Brazilian poll comes with a registration number, and it makes the polls easier to audit than the market price. The wider argument about which source is more accurate over time is in market, poll or pundit.

Why is Polymarket blocked in Brazil, and what is still legal?

Resolução CMN 5.298, published by the Banco Central do Brasil on 24 April 2026 and in force since 4 May 2026, forbids offering or trading in Brazil any derivative whose underlying is a sports, online game, political, electoral, social, cultural or entertainment event, and extends the ban to foreign derivatives offered inside Brazil (Banco Central do Brasil). Polymarket began removing Brazilian users in May 2026 (Exame, May 2026).

That produces a strange situation. The largest market on the Brazilian election is priced by people who mostly cannot vote in it and, if they are in Brazil, cannot legally trade in it. Núcleo Jornalismo reported on 29 May 2026 that Polymarket odds were nonetheless being quoted as a polling source by right wing YouTube channels in Brazil after the ban (Núcleo Jornalismo, 29 May 2026). A price quoted as a poll, produced by a population that is not the electorate, is a specific kind of measurement error, and it is worth naming when you read one.

What stays legal is the forecast itself. Resolução CMN 5.298 governs derivative contracts, which require a payoff. Publishing a dated public prediction with no stake, no payout and no prize is not a derivative and not a wager. The detail is in Polymarket blocked in Brazil. This is not legal advice.

How do I record a forecast on the Brazilian election?

Post a call on the same events, with the timestamp and the market price frozen next to it. On insiderz there is no money at any point: you say yes or no and how sure you are, and the call is locked the second it is posted, with the time and the Polymarket price at that moment. When the election resolves, the call is scored against that price. Being right where the market was wrong is what counts, so a call on the runoff made in September is worth far more than the same call made on 24 October.

The election gives you two scoring dates three weeks apart, on 5 and 26 October, which makes it one of the cleanest public tests of the year. The leaderboard ranks people on Beats market, Events, Edge and Early.

Browse the open events on the events page, read what other people are calling in the calls feed, and check the forecaster's calendar for what comes after 25 October.

Method

Every price here was read directly from the Polymarket Gamma API on 4 September 2026 and the API URLs are listed in the sources, so anyone can re-read them. Prices are the yes price of the named contract as returned. Volumes are event level, in US dollars, from the same endpoint.

Poll figures are quoted from the published release for each poll, with fieldwork dates, sample size and margin of error stated, and never averaged across firms with different methods. No number on this page comes from a screenshot of a chart.

This page is updated weekly until 25 October 2026. insiderz launched in September 2026 and has no accuracy record of its own yet, so nothing here is presented as evidence about insiderz.