Brazil's top electoral court has ordered Meta to pay 7.5 million reais ($1.34 million; €1.22 million) for failing to fully comply with judicial orders during last month's presidential election.
However, the judicial body has so far found no evidence that Meta deliberately acted to influence the election outcome.
Ahead of the runoff vote on October 25, leftist President Luiz Inacio Lula da Silva's coalition filed a complaint, accusing Meta of "algorithmic manipulation" favoring his far-right candidate Flavio Bolsonaro.
Platforms owned by Meta include Facebook, Instagram and WhatsApp.
Meta told the court last month that it had implemented measures to guarantee equal treatment for both campaigns.
The Superior Electoral Court (TSE) unanimously ruled on Tuesday to impose the 7.5 million reais fine on the US tech giant.
Meta missed deadlines and lacked transparency in its investigation, the court said.
On the other hand, the court's reporting judge Marco Aurelio Belizze wrote in his ruling that there were no preliminary evidence indicating that any intentional actions were taken to influence the election.
"That conclusion would require robust evidence, to be produced through the appropriate legal proceedings," he said.
According to Bellizze, the fine was based on Meta's overall handling of the court orders, including delays, incomplete disclosures, and challenges in verifying some of the information it provided.
