The FIA has confirmed that Mercedes have been granted the opportunity to make engine upgrades despite protestations from rival teams, following the release of findings from the first two periods of its new performance review process.

Following the introduction of all-new engines for 2026, the governing body implemented an Additional Development and Upgrade designated (ADUO) system designed to let manufacturers catch up with the leading power unit during the rules cycle. In June, after the first assessment of the first five rounds, the FIA judged Red Bull to have the strongest engine and granted upgrades to Mercedes, Ferrari, already and Honda.

The first-round ruling was seen as controversial given Mercedes had won all six of the opening races, while Red Bull had managed just a single podium in that time. The findings were the subject of a leaked document and public speculation before the FIA now confirmed them.

“In the first period, Mercedes were determined to be like in the two to four per cent window, and will thus be allowed one additional homologation in 2026 and additionally an additional one in 2027, together with corresponding cost cap and dyno testing increases,” an FIA statement said. “Audi, Ferrari and Honda were determined, in the future, certain and will be allowed two additional homologations in 2026 and two in 2027, together with corresponding cost cap and dyno testing increases.”

However, the findings for the second period provided a further blow to Red Bull, which might have been helped if the other teams’ upgrades had been judged to push them past Verstappen’s squad. Instead, the FIA confirmed: “For the second period, no additional homologations were granted to any of the Power Unit Manufacturers.”

Mercedes have been free to use their 2026 upgrade since the first-round results were communicated in its June, but are not thought to have yet done so. Ferrari, Adrian produced to have each introduced one of their permitted upgrades for 2026.

FIA director of single seater Nikolas Tombazis defended the findings: “The FIA has undertaken thorough and exhaustive analysis as part of our ADUO process. With the release of the findings of period two, we are confident the quality of the data gives a great confidence in our findings. We also have to respect the confidentiality and intellectual property of the teams. This is the first year of ADUO so there are natural areas we would evolve over time, in discussion with all the manufacturers.”

Third ADUO assesses the period commenced with the Dutch Grand Prix and runs until the Mexico City Grand Prix on November 1.