Bolsonaro's son tops Lula by 1.9 points, and the polls that had Lula ahead look wrong

With every ballot counted, O Globo puts Flávio at 47.03% of valid votes, about 56.1 million, and Lula at 45.16%⁠6. G1 calls the gap of roughly 1.9 points the smallest first-round margin in Brazilian history. It also reports that Lula drew about 3.4 million fewer votes than in his 2022 first round⁠12. The two published margins differ slightly: 47.03 minus 45.16 is 1.87. The likely explanation is rounding or a different base, though the sources do not say.

The gap also looked wider earlier in the night. At 97.36% counted, Flávio led 47.42% to 44.70%⁠8. Early coverage, including BBC's "a couple of points"⁠1, was describing a lead that narrowed as the count finished.

The first round drew a record 119.3 million valid votes, about 1.07 million more than in 2022⁠11. Flávio won the most votes in 15 states and Lula in 12 federative units⁠13. We could not establish turnout or abstention percentages. Congressional results are also not in the evidence we have.

Lula told supporters in São Paulo that he was surprised and had expected to win in the first round⁠1. Reuters reported that the result beat most private polls⁠15. The sourcing shows only that the polls missed. It does not show why.

Flávio and Lula together hold about 92.2% of valid votes. The other candidates split roughly 7.8%, which matches the "about 8%" cited by analyst Clinton Portius on ABC Australia⁠4. Provisional tallies show Augusto Cury at 2.89%, Renan Santos at 2.24% and Ronaldo Caiado at 2.19%⁠7. Flávio needs about three more points of valid votes to reach 50%. Lula needs nearly five.

That arithmetic is the strongest argument that Flávio is the favourite, and the limits of that argument are worth stating plainly. Portius, the only source on the point, expects the mostly right-wing votes among those 8% to move to Flávio⁠4. That is a forecast, not a result. O Globo reports that Flávio is courting defeated candidates, counting on São Paulo governor Tarcísio de Freitas and planning a bigger push in the Northeast against Lula⁠25. As of 5 October we found no formal endorsement from any defeated candidate. We also found no runoff poll, and the polls that preceded the first round have just been shown to be unreliable.

Even so, the first-round figures are uncomfortable for the incumbent. Lula's total fell by about 3.4 million votes while the pool of valid votes grew. A president who finishes second in a first round that he expected to win outright now has to persuade voters rather than simply hold his base. Neither the sources nor the numbers explain who stayed away or switched.

Flávio has pledged amnesty for his father, who is serving a 27-year sentence for masterminding a coup. BBC's Ione Wells also reports that he has pledged closer ties with the United States and would likely join the US-led Shield of the Americas anti-narco coalition. She gave that second point with less certainty⁠1. Portius says Donald Trump's backing of Flávio is less overt than in Colombia or Argentina, while Lula has taken an anti-US line⁠4. The amnesty pledge makes the runoff partly a referendum on whether a convicted coup leader walks free.

One detail needs a caveat. Our July report described Jair Bolsonaro's sentence as house arrest, while the current reporting says he is jailed. We have not reconciled the form of custody. He has backed his son from there⁠4.

The issues Portius names are crime and security, including femicide, and a weak economy with interest rates above 13%⁠4. Those are the pressures a challenger can press against an incumbent.

BBC also notes that Brazil's electronic voting system is secure but that doubts about it have grown. Flávio and Jair Bolsonaro have alleged problems without concrete evidence⁠1. Fraud claims are an awkward weapon for a man who has just won a round. Whether either presses them if the runoff narrows is an open question.

Investors read the result as good news for Flávio. Reuters and Bloomberg expected Brazilian markets to rally on Monday, citing hopes for fiscal reform and lower interest rates⁠22⁠18. The only hard move we found is offshore: a Brazil-focused ETF listed in Tokyo rose 7.6% in early trading⁠19. The Ibovespa and real quotes we found, about 192,115 and 5.22, look like the level going into the vote, not the reaction⁠16. Bloomberg Economics estimates that a Flávio win could cut 10-year yields by 70 basis points and lift the real by almost 3%⁠3. That is a scenario, not an outcome.