Coventry Building Society lowered its common equity Tier 1 ratio as of June 30 by 1.6 percentage points to 32.6% from 34.2% after it found that it had mistakenly calculated its risk-weighted assets.

The company said that while updating internal ratings-based models it uses to calculate RWAs, it found that it failed to apply the necessary 6% scalar to the core model outputs, which would have increased its total RWAs by 4.6%.

Despite the error, the building society said it expects its CET1 ratio to reflect a considerable capital surplus above regulatory requirements, noting that the change will not affect its leverage ratio, which the company expects to be its binding capital measure in the future.