diff --git a/app/models/validations/sales/soft_validations.rb b/app/models/validations/sales/soft_validations.rb
index 0bffe1234..b60c9912c 100644
--- a/app/models/validations/sales/soft_validations.rb
+++ b/app/models/validations/sales/soft_validations.rb
@@ -75,4 +75,11 @@ module Validations::Sales::SoftValidations
 
     !grant.between?(9_000, 16_000)
   end
+
+  def monthly_charges_over_soft_max?
+    return unless type && mscharge && proptype
+
+    soft_max = old_persons_shared_ownership? ? 550 : 300
+    mscharge > soft_max
+  end
 end
diff --git a/spec/models/validations/sales/soft_validations_spec.rb b/spec/models/validations/sales/soft_validations_spec.rb
index dc873bc97..40e658c73 100644
--- a/spec/models/validations/sales/soft_validations_spec.rb
+++ b/spec/models/validations/sales/soft_validations_spec.rb
@@ -593,4 +593,66 @@ RSpec.describe Validations::Sales::SoftValidations do
       expect(record).to be_staircase_bought_above_fifty
     end
   end
+
+  describe "#monthly_charges_over_soft_max?" do
+    it "returns false if mscharge is not given" do
+      record.mscharge = nil
+      record.proptype = 4
+      record.type = 2
+
+      expect(record).not_to be_monthly_charges_over_soft_max
+    end
+
+    it "returns false if proptype is not given" do
+      record.mscharge = 999
+      record.proptype = nil
+      record.type = 2
+
+      expect(record).not_to be_monthly_charges_over_soft_max
+    end
+
+    it "returns false if type is not given" do
+      record.mscharge = 999
+      record.proptype = 4
+      record.type = nil
+
+      expect(record).not_to be_monthly_charges_over_soft_max
+    end
+
+    context "with old persons shared ownership" do
+      it "returns false if the monthly charge is under 550" do
+        record.mscharge = 540
+        record.proptype = 4
+        record.type = 24
+
+        expect(record).not_to be_monthly_charges_over_soft_max
+      end
+
+      it "returns true if the monthly charge is over 550" do
+        record.mscharge = 999
+        record.proptype = 4
+        record.type = 24
+
+        expect(record).to be_monthly_charges_over_soft_max
+      end
+    end
+
+    context "with non old persons type of ownership" do
+      it "returns false if the monthly charge is under 300" do
+        record.mscharge = 280
+        record.proptype = 4
+        record.type = 18
+
+        expect(record).not_to be_monthly_charges_over_soft_max
+      end
+
+      it "returns true if the monthly charge is over 300" do
+        record.mscharge = 400
+        record.proptype = 4
+        record.type = 18
+
+        expect(record).to be_monthly_charges_over_soft_max
+      end
+    end
+  end
 end