September 18, 2026

1. Prediction market

The presidential election winner contract widened the spread for the third day, and this time both sides moved. In the confirmed reading of September 18, at 18:59 BRT, Flávio Bolsonaro stands at 56.50% (USD 11.02M), 1.80pp above the 54.70% of September 17, and Lula fell 2.00pp, to 42.50% (USD 11.36M). The distance went from 10.20pp to 14.00pp, with total presidential volume at USD 151.46M accumulated.

Flávio's 56.50% stands above the highest value in the recorded readings of his series, 56.40% earlier the same day, in a series that begins on April 14. Lula stands 25.00pp below the top of his series, 67.50% on August 16. Renan Santos gave up 0.20pp, to 0.95%, below the lowest value ever recorded.

The largest move of the day is not in the winner contract. In the first-round runner-up contract Flávio fell 7.00pp, to 69.50% (USD 953 thousand), and Lula rose 6.70pp, to 29.35% (USD 807 thousand). Whoever becomes more likely to win becomes less likely to finish second, and that book moved almost four times more than the winner one.

In the third-place contract, Renan Santos rose 5.00pp, to 49.00% (USD 347 thousand), and opened 8.00pp over Augusto Cury, who fell 1.90pp, to 41.00% (USD 226 thousand). Ronaldo Caiado gave up 2.00pp, to 10.50% (USD 137 thousand). The Supreme Court impeachment contract stands at 4.60% (USD 92 thousand), 0.45pp below the previous day, and in the Senate contract the Liberal Party stands at 83.50% (USD 261 thousand).

2. What the polling firms recorded

The two national polls the TSE register listed for September 17, and which that day's briefing declared it did not have, came out at night. Datafolha interviewed 2,002 people in person from September 15 to 16, a margin of 2pp and register BR-04029/2026. In the first round Lula has 39% and Flávio 36%, with Cury at 6%, Caiado at 4%, Renan at 3% and Zema at 2%. In the runoff Lula has 46% and Flávio 44%, the same numbers as the firm's two previous rounds, and the two tie on rejection, at 47% each. Government assessment is 48% approval against 50% disapproval.

Futura Inteligência, contracted by 100% Cidades, interviewed 2,000 voters by phone from September 11 to 15, a margin of 2.2pp and register BR-00749/2026. In the first round Lula has 38.3% and Flávio 37.7%. In the runoff Flávio has 48.1% and Lula 43.7%, outside two margins, and Lula is rejected by 49.7% against 45.3% for Flávio. Government assessment is 44.1% against 53.1%. The TSE also listed Veritá for September 18, with 40,500 interviews, and its numbers were not published at the time of capture.

Polling calendar, next 7 days

Polls registered with the TSE scheduled for publication between Sep 19 and Sep 25. Inclusion in the table does not mean confirmed publication, because firms can delay or cancel a release. Filters applied: national scope and sample size of at least 1,000.

Source: public TSE register via the AFOS API. Samples of 3,000 or more in bold. The table lists the 7 national polls in the window, and 49 records from the same period were left out by scope or by sample size. The label on BR-00548/2026 comes out marked because it derives from the sampling plan, a field this firm fills with the same text in state-level polls. The status is registered, not published.

3. What the press covered

The 15% increase in Bolsa Família, announced by Lula on the morning of September 17, raises the floor from R$ 600 to R$ 691 and starts being paid on October 19, between the first and second rounds, according to O Globo. BBC News Brasil recorded the announcement the same day.

The measure went to the courts in two moves. On September 17, at the Superior Electoral Court, André Mendonça rejected a federal deputy's filing against the increase for lack of standing, and wrote in the decision that this is no pronouncement on the legality or constitutionality of the measure. That same night, Renan Santos filed his own petition, and Mendonça was drawn as rapporteur again, according to Estadão. On September 18, the Solicitor General's Office asked the Supreme Court to recognise the decree as constitutional, according to CartaCapital and Metrópoles. Flávio Bolsonaro disavowed his ally's filing and promised to keep the increase if elected, according to UOL.

In the Banco Master case, the defence of Daniel Vorcaro, detained since November 17, 2025, asked for his pretrial detention to be revoked and cited the unresolved state of the case at the Supreme Court as an argument, according to O Globo. The defence stated it will appeal to the full bench if Edson Fachin keeps the detention, according to Gazeta do Povo. Gilmar Mendes acknowledged having had a meeting with Vorcaro and said he voted against Banco Master in a case worth up to R$ 145 billion.

4. Divergences of the day

In summary

The spread widened with both sides moving. Flávio rose 1.80pp, to 56.50%, above the highest value ever recorded in his series, and Lula fell 2.00pp, to 42.50%. The distance reached 14.00pp.

The runner-up book moved almost four times more. Flávio fell 7.00pp there and Lula rose 6.70pp, the mirror of the main move, measured in a contract whose price has more room to travel.

The two national polls from the previous day invert each other. Datafolha and Futura/100% Cidades give the runoff to opposite sides, and the judicial dispute over the increase reached the Supreme Court at the government's own hand.

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Fontes consultadas

matérias com link direto para a notícia (veículos âncora):

• G1 · Datafolha, first round: Lula, 39%; Flávio Bolsonaro, 36%; Cury, 6%; Caiado, 4%; Renan, 3%; Zema, 2%
• Exame · Futura poll: Flávio Bolsonaro grows and ties technically with Lula in the first round
• G1 · Mendonça rejects filing questioning the Bolsa Família increase without ruling on the legality of the measure
• G1 · Renan Santos goes to the TSE against the Bolsa Família increase
• Estadão · Mendonça will be rapporteur of Renan Santos's filing against the Bolsa Família increase made by Lula
• CartaCapital · AGU asks the Supreme Court to recognise the constitutionality of the Bolsa Família increase
• Metrópoles · Lula government asks the Supreme Court to recognise the validity of the Bolsa Família increase
• O Globo · Flávio Bolsonaro disavows Zé Trovão over filing that questioned Lula's Bolsa Família increase
• O Globo · Vorcaro's defence asks for detention to be revoked and cites the unresolved Banco Master case and the Supreme Court crisis
• Gazeta do Povo · Vorcaro's defence will appeal to the full bench of the Supreme Court if Fachin keeps the detention
• CartaCapital · Gilmar acknowledges meeting with Vorcaro and highlights vote against Banco Master in a case worth up to R$ 145 billion

matérias secundárias (URL de redirecionamento, clique resolve à matéria):

• G1 · Datafolha: Lula and Flávio Bolsonaro tie on rejection, at 47% each
• UOL Notícias · Futura/100% Cidades: Flávio Bolsonaro appears ahead of Lula in the runoff
• CNN Brasil · Futura: Lula is rejected by 49.7%; Flávio, by 45.3%
• BBC News Brasil · Lula announces a 15% increase in Bolsa Família, on the eve of the election
• O Globo · Bolsa Família increase starts being paid on October 19, between the first and second rounds of the elections
• UOL Notícias · After calling it 'illegal', Flávio promises to keep the Bolsa Família increase

Fontes técnicas: Polymarket (live quotes via the AFOS proxy, confirmed reading on Sep 18 at 18:59 BRT), TSE register (official electoral polls).