1. Prediction market

The winner contract widened for a second straight day. In the confirmed reading of September 11, at 1:41 PM BRT, Flávio Bolsonaro stands at 53.95% (USD 10.36M) and Lula at 42.50% (USD 10.69M), against 52.85% and 43.50% on September 10. The total volume accumulated in the presidential book adds up to USD 148.03M.

The size of the move is what the direction hides. On September 10 Flávio travelled 6.60pp and Lula 9.00pp, and the book changed hands at the top; on September 11 Flávio travelled 1.10pp and Lula 1.00pp, about one tenth of that. The gap went from 9.35pp to 11.45pp, and the 53.95% is the highest point in the series, opened on April 14, above the previous 53.20%.

The second-place contract undid the previous day's move: Flávio rose 3.00pp, to 74.50% (USD 725 thousand), and Lula fell 1.60pp, to 22.90% (USD 601 thousand). In the third-place contract the distance more than doubled in 24 hours: Augusto Cury rose 3.65pp and stands at 52.90% (USD 160 thousand) and Renan Santos fell 4.00pp, to 38.50% (USD 297 thousand), the largest drop of the round.

The Supreme Court impeachment contract before 2027 almost doubled, from 4.35% to 8.30% (USD 90 thousand), and remains 11.00pp below the peak of the series, of 19.30% on September 4. The volume of USD 90 thousand is small enough that isolated orders can move the price. In the Senate, Partido Liberal stands at 83.00% (USD 261 thousand).

2. What the pollsters registered

The national poll entering the panel is AtlasIntel with Bloomberg, fieldwork from September 4 to 9, 5,000 interviews, a margin of 1.0 point and TSE registration BR-01452/2026. In the first round it measures Lula 43.0%, Flávio Bolsonaro 37.4%, Augusto Cury 6.6% and Renan Santos 6.5%.

Its value is being the same house as on August 31, with the same method and margin, which allows comparison without mixing pollsters. Lula goes from 43.4% to 43.0% and Flávio goes from 33.7% to 37.4%: the lead of 9.7 points became 5.6 in eleven days, and it shrank because Flávio rose, not because Lula fell. Across the five runoff pairings, Flávio comes out ahead of Lula by 46.4% to 46.2%, Zema by 46.2% to 46.0% and Caiado ties at 45.7%, three differences that fit inside two margins of 1.0 point and are therefore a statistical tie. Lula wins the two pairings that fall outside the margin, against Cury by 43.8% to 41.1% and against Renan by 46.0% to 33.8%. The TSE record carries 879 presidential polls.

Polling calendar, next 7 days

Polls registered with the TSE scheduled for publication between Sep 14 and Sep 16. Appearing in the table does not mean publication is confirmed, because pollsters can delay or cancel a release. Filters: national scope and a sample of 1,000 or more, with each registration linked to the TSE public record.

Date	Pollster	Sample	Scope	TSE registration	Conf.
Sep 14	Quaest	2,004	national	BR-03607/2026	0.9
Sep 14	NEXUS	2,000	national	BR-04076/2026	0.7
Sep 15	MDA	2,002	national	BR-06902/2026	0.9
Sep 15	Indexa	2,000	national	BR-03482/2026	0.7
Sep 16	Datatrends	2,000	national	BR-08691/2026	0.7
Sep 16	American Analytics	2,000	national	BR-01431/2026	0.7

Source: public TSE record via the AFOS API. Samples of 3,000 or more in bold. The table lists the 6 NATIONAL polls in the window; 46 records from the same period were left out by scope or by sample. The status is registered, not published.

3. What the press covered

The most consequential act of the day is one of publicity, not of investigation. At 11:44 PM on September 10, Mendonça granted a request by Fachin and lifted the secrecy on 14 proceedings in the Master case, and it was that lifting which made the rest public.

The rest is that Flávio Bolsonaro has been under Federal Police investigation since July 2026, authorised by Mendonça himself, for money laundering, currency evasion and corruption in the financing of the film Dark Horse. The investigation did not begin on September 11: what changed is that it stopped running under seal. The senator defended the decision that put him under investigation.

On the same day, Alexandre de Moraes accused Mendonça of being selective and said that 180 documents were left out of the disclosure. Lula praised Fachin and defended investigating Supreme Court justices. Augusto Cury signalled that he may back Flávio in a runoff.

4. Divergences of the day

The pollsters stopped disagreeing before the price changed hands. Between August 21 and September 3, the Lula against Flávio pairing flipped sign seven times across the registered national polls, and two came out on the same August 26, with Gerp giving Flávio a 5 point lead and Indexa giving Lula a 5 point lead. From September 6 the alternation ceases: eight consecutive readings, from eight houses, and none with Lula ahead. The winner contract only changed hands on September 10, four days later. AFOS records the order and does not claim that one produced the other.

What the eight have in common is not Flávio leading, it is Lula ceasing to lead. Six of the eight fit inside two margins of their own house, which makes them a statistical tie and not a lead, and only Veritá on September 6 and Gerp on September 9 fall outside it. A book marking 11.45pp and a house measuring two tenths in the head-to-head pairing are not measuring the same quantity: price is the probability of winning the election, a poll is stated voting intention, and AFOS does not subtract one from the other.

News and price, in the order in which they happened. The disclosure that Flávio Bolsonaro has been under investigation since July came out on the morning of September 11, and the price reading on this page is from 1:41 PM BRT, therefore later than it. In that reading his contract rose 1.10pp and renewed the peak of its own series. Both facts are measured, the link between them is not, and the page records the sequence without attributing cause.

In summary

The presidential contract widened for a second day, with one tenth of the intensity of the first. The gap went from 9.35pp to 11.45pp with 1.10pp and 1.00pp, against 6.60pp and 9.00pp on September 10, and the 53.95% is the highest point in the series.

The poll of the day is the cleanest comparison of the week, because it repeats its own house. In AtlasIntel, between August 31 and September 10, Lula's lead fell from 9.7 to 5.6 points and the five runoff pairings all moved in the same direction.

The disagreement between houses stopped on September 6 and the price changed hands on September 10. That is four days between one instrument and the other, measured across 522 series points and 24 pairings registered with the TSE. Next week brings six national polls between September 14 and 16, none confirmed so far.

Fontes consultadas

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

matérias secundárias (URL Google News redirect, clique resolve à matéria):

Fontes técnicas: Polymarket (live quotes via the AFOS proxy, fetched Sep 11, 1:41 PM BRT), registro TSE (official electoral polls).

September 11, 2026