diff --git a/app/models/validations/sales/financial_validations.rb b/app/models/validations/sales/financial_validations.rb
index 21f3743ca..6e9e0814c 100644
--- a/app/models/validations/sales/financial_validations.rb
+++ b/app/models/validations/sales/financial_validations.rb
@@ -52,6 +52,16 @@ module Validations::Sales::FinancialValidations
     end
   end
 
+  def validate_percentage_bought_at_least_threshold(record)
+    return unless record.stairbought && record.type
+
+    if ([2, 18, 16, 24].include? record.type) && record.stairbought < 10
+      record.errors.add :stairbought, I18n.t("validations.financial.staircasing.percentage_bought_must_be_at_least_threshold", percentage: 10)
+    elsif record.type == 30 && record.stairbought < 1
+      record.errors.add :stairbought, I18n.t("validations.financial.staircasing.percentage_bought_must_be_at_least_threshold", percentage: 1)
+    end
+  end
+
   def validate_child_income(record)
     return unless record.income2 && record.ecstat2
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index d21bb5b5c..7c7ffe1ee 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -302,6 +302,7 @@ en:
       staircasing:
         percentage_bought_must_be_greater_than_percentage_owned: "Total percentage buyer now owns must be more than percentage bought in this transaction"
         older_person_percentage_owned_maximum_75: "Percentage cannot be above 75% under Older Person's Shared Ownership"
+        percentage_bought_must_be_at_least_threshold: "The minimum increase in equity while staircasing is %{percentage}%"
 
     household:
       reasonpref: