The Fédération Internationale de l'Automobile (FIA) has concluded its third and final Additional Development and Upgrade Opportunities (ADUO) review of the 2026 Formula 1 season, confirming that no power unit manufacturer will receive additional homologated upgrades following the assessment covering Races 12 to 18. The findings have been communicated to all power unit manufacturers.

What the Final ADUO Review Found

Despite shifts in the performance gaps between manufacturers during the third review period — which concluded after the United States Grand Prix — the FIA determined those changes fell short of the thresholds required to trigger new upgrade allowances.

'For the third period, the relative performance gaps to the leading ICE evolved, but these changes did not result in any additional homologations being granted to the Power Unit Manufacturers,' the FIA said in an official statement.

The outcome mirrors the second review period, which also yielded no additional homologations, meaning the upgrade allocation framework established after the first review remains the operative baseline for the remainder of the season and into 2027.

How ADUO Works and Why It Matters

The ADUO mechanism, embedded in Article C4 of the 2026 Formula 1 Technical Regulations, allows power unit manufacturers whose internal combustion engine (ICE) performance trails the best-performing ICE by at least 2% across defined review windows to introduce additional homologated upgrades — both within the current season and the following one. Manufacturers in that bracket also benefit from expanded cost cap allowances and additional dyno testing time.

Three review periods govern each season: the first concluded after the Canadian Grand Prix, the second after the Hungarian Grand Prix, and the third after the United States Grand Prix.

What Happened in the First Review

The first assessment, conducted post-Canada, was the only one to trigger additional homologations. Mercedes were found to sit within the 2–4% performance gap window and were granted one additional homologation in 2026 and one in 2027, along with corresponding cost cap and dyno testing increases.

Audi, Ferrari, and Honda were assessed as more than 4% adrift of the benchmark and were each awarded two additional homologations in the current season and two more in 2027, with equivalent allowance increases.

Notably, Red Bull-Ford was designated the ICE benchmark at that stage, despite Mercedes emerging as arguably the strongest package in the opening half of the 2026 season on overall car performance. That classification has practical implications: Red Bull-Ford will enter 2027 without additional development headroom from the ADUO process.

FIA's Confidence in the Process

FIA Director of Single Seater Nikolas Tombazis defended the rigour of the methodology. 'The FIA has undertaken extensive analysis as part of the review of ADUO this year. Based on the quality of the data and the robustness of the assessment process, we are confident in our findings and the conclusions reached,' he said.

Tombazis also signalled that refinements to the system are already in discussion. 'The first year of implementation has also reinforced our belief that the ADUO concept is the right one for Formula 1. However, it is important that the system continues to evolve to ensure it remains efficient, relevant and fit for purpose. To that end, we have been working closely with the Power Unit Manufacturers and teams to explore refinements to the methodology that will support the continued effectiveness of ADUO in future seasons,' he added.

What This Means Going Into 2027

With the final ADUO review now complete, the upgrade picture for the 2026 season is frozen. Manufacturers that received homologations in the first review retain those allowances; no new ones have been added. The focus now shifts to how the FIA and manufacturers jointly refine the ADUO framework before it is applied again in the next campaign, with Tombazis indicating that methodological changes are actively being explored.