Guild renown decay formula
The formula for renown decay is a level-based multiplier times an account-based multiplier (LevelMultiplier * AccountMultiplier). The account-based multiplier is the Modified Guild Size + 10. The level-based multiplier can be looked up in the list below.
Note: Minimum Modified Guild Size is 10! Account-based multiplier is therefore ( Max(Modified Guild Size,10) + 10 )