Brazil's President and presidential candidate Luiz Inacio Lula da Silva waves a national flag during a campaign rally in Sao Paulo, Brazil, on Sept. 26, 2026.

Miguel Schincariol | Afp | Getty Images

Luiz Inácio Lula da Silva was reelected president of Brazil on Sunday in a runoff election, an upset that prediction markets odds failed to anticipate.

Lula defeated Flávio Bolsonaro , the right-wing candidate and son of former president Jair Bolsonaro, by 51.8% to 48.2%, according to the country's Superior Electoral Court.

As late as Sunday afternoon, Lula remained a significant underdog on prediction markets. Even just after 8:30 p.m. ET on Sunday, Lula's odds were at 21% on Kalshi.

Bolsonaro's odds on prediction markets surged after first-round voting on Oct. 4, with both Kalshi and Polymarket giving Bolsonaro an over 80% chance of ousting Lula.…