Diminishing returns

Diminishing returns is a Gameplay Mechanic in Paladins that makes many different types of effects (both positive and negative effects) less effective when stacked up. These effects can be gained from champion skills, cards and/or items.

Champions will always receive the full value of their single highest bonus in an attribute, and all other bonuses will diminish on top of that value (e.g. a champion has 4 Life Steal bonuses: 30%, 20%, 20%, and 10%. The champion is guaranteed to get the full value from the 30% bonus, the other will diminish on top of that 30%. Their total Life Steal will be 55.00%). Movement Speed has a maximum increase of 150% while all other attributes have a maximum increase of 95%. Diminishing Returns will never kick in until a champion receives at least a 30% change in an attribute.

Reload Speed bonuses are an exception and stack additively and cap at 60% (50% Reload Speed bonus from Nimble Fingers 5 will not be diminished on top of 40% Reload Speed bonus from Deft Hands 2 but it will cap at 60%).

Damage Taken debuffs and Damage amps don't diminish on top of each other, they count as different effects.

Attributes that oppose each other will stack their diminished values additively against each other. Movement Speed opposes Slow debuffs. Damage Reduction opposes Damage Taken debuffs. Healing Increase opposes Healing Reduction.

Here is the formula for diminishing returns for attribute increases:

$\%y = \begin{cases} \%m + (1.5 - \%m) \times \frac{\%x - \%m}{\%x + 1.06} & \text{if movement speed bonus}\\ \%m + (0.95 - \%m) \times \frac{\%x - \%m}{\%x + 0.5} & \text{if other attribute bonus}\\ \end{cases}$

$\text{with:}$

$\%y = \text{final diminished value in percent}$

$\%m = \text{highest single attribute bonus in percent}$

$\%x = \text{total attribute boni in percent}$

$\%x = \sum_{i=1}^{n}\%a_i$

$\text{with: } n = \text{ the total count of attributes and } \%a_i = \text{ the value of an attribute in percent}$

You can find a Diminishing Returns Calculator here.