diff --git a/specs/abtesting/common/parameters.yml b/specs/abtesting/common/parameters.yml
index f58bd7e47b8..41ae614dca3 100644
--- a/specs/abtesting/common/parameters.yml
+++ b/specs/abtesting/common/parameters.yml
@@ -69,11 +69,13 @@ currencies:
       revenue: 120.0
       mean: 53.7
       standardDeviation: 12.3
+      winsorizedAmount: 23.0
     EUR:
       currency: EUR
       revenue: 100.0
       mean: 43.7
       standardDeviation: 10.3
+      winsorizedAmount: 10.0
   additionalProperties:
     $ref: '#/currency'
     x-additionalPropertiesName: currency code
@@ -100,6 +102,11 @@ currency:
       format: double
       description: Standard deviation for this currency.
       example: 12.3
+    winsorizedAmount:
+      type: number
+      format: double
+      description: The amount of revenue for this currency that was removed after capping purchase amounts to the 95th percentile.
+      example: 23.0
 
 filterEffects:
   type: object