Senator Flávio Bolsonaro has taken the lead over incumbent President Luiz Inácio Lula da Silva in new polling ahead of Brazil's Oct. 25 presidential runoff, a dramatic swing that comes as the country's Supreme Court has ordered the arrest of the candidate's brother, federal deputy Eduardo Bolsonaro.

A fresh poll cited by Bloomberg shows Flávio Bolsonaro, a senator for Rio de Janeiro and member of the right-wing Liberal Party, ahead of Lula after neither candidate won a majority in the first round of voting. Betting markets have moved sharply in the same direction, with Polymarket odds giving Flávio roughly an 89 percent chance of winning the presidency to Lula's 11.5 percent.

An Arrest Order Complicates the Family's Momentum

The surge has been complicated by Brazil's Supreme Court, which ordered the arrest of Eduardo Bolsonaro, Flávio's brother and a federal deputy for São Paulo, according to UPI. Eduardo, who spent time in the United States earlier in 2025 while on leave from his position, called the ruling arbitrary, ill-timed and futile. The order's precise legal basis was not detailed in early reporting.

POLYMARKET GIVES FLÁVIO AN 89 PERCENT CHANCE OF WINNING.

Investors have responded favorably to the shift. Brazil's benchmark Ibovespa stock index climbed 1.38 percent to a record 209,067 points on Friday, with traders citing optimism tied to a possible Bolsonaro win, according to Rio Times. Flávio has signaled he would pursue a sharp pivot on climate and Amazon policy if elected, a contrast with his family's historical environmental record.

The runoff vote is set for Oct. 25. With the arrest order against his brother now looming over the race, analysts say the campaign's final two weeks will test whether legal controversy helps or hurts a Bolsonaro bid that, for now, has the momentum.