diff --git a/app/models/sales_log.rb b/app/models/sales_log.rb
index aa3eb1c09..a9e8b807e 100644
--- a/app/models/sales_log.rb
+++ b/app/models/sales_log.rb
@@ -211,4 +211,8 @@ class SalesLog < Log
   def old_persons_shared_ownership?
     type == 24
   end
+
+  def shared_owhership_scheme?
+    ownershipsch == 1
+  end
 end
diff --git a/app/models/validations/sales/sale_information_validations.rb b/app/models/validations/sales/sale_information_validations.rb
index c42c42ccc..53d76fd48 100644
--- a/app/models/validations/sales/sale_information_validations.rb
+++ b/app/models/validations/sales/sale_information_validations.rb
@@ -54,4 +54,13 @@ module Validations::Sales::SaleInformationValidations
       end
     end
   end
+
+  def validate_basic_monthly_rent(record)
+    return unless record.mrent && record.ownershipsch && record.type
+
+    if record.shared_owhership_scheme? && !record.old_persons_shared_ownership? && record.mrent > 9999
+      record.errors.add :mrent, I18n.t("validations.sale_information.monthly_rent.higher_than_expected")
+      record.errors.add :type, I18n.t("validations.sale_information.monthly_rent.higher_than_expected")
+    end
+  end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 3dd612e8e..67a819e52 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -426,6 +426,8 @@ en:
       previous_property_type:
         property_type_bedsit: "A bedsit can not have more than 1 bedroom"
       discounted_ownership_value: "Mortgage, deposit, and grant total must equal £%{value_with_discount}"
+      monthly_rent:
+        higher_than_expected: "Basic monthly rent must be between £0 and £9,999"
 
   soft_validations:
     net_income:
diff --git a/spec/models/validations/sales/sale_information_validations_spec.rb b/spec/models/validations/sales/sale_information_validations_spec.rb
index d2921e8f0..8783efd09 100644
--- a/spec/models/validations/sales/sale_information_validations_spec.rb
+++ b/spec/models/validations/sales/sale_information_validations_spec.rb
@@ -371,4 +371,61 @@ RSpec.describe Validations::Sales::SaleInformationValidations do
       end
     end
   end
+
+  describe "#validate_basic_monthly_rent" do
+    context "when within permitted bounds" do
+      let(:record) { build(:sales_log, mrent: 9998, ownershipsch: 1, type: 2) }
+
+      it "does not add an error" do
+        sale_information_validator.validate_basic_monthly_rent(record)
+
+        expect(record.errors[:mrent]).not_to be_present
+        expect(record.errors[:type]).not_to be_present
+      end
+    end
+
+    context "when the rent is blank" do
+      let(:record) { build(:sales_log, mrent: nil, ownershipsch: 1, type: 2) }
+
+      it "does not add an error" do
+        sale_information_validator.validate_basic_monthly_rent(record)
+
+        expect(record.errors[:mrent]).not_to be_present
+        expect(record.errors[:type]).not_to be_present
+      end
+    end
+
+    context "when the type is old persons shared ownership" do
+      let(:record) { build(:sales_log, mrent: 100_000, ownershipsch: 1, type: 24) }
+
+      it "does not add an error" do
+        sale_information_validator.validate_basic_monthly_rent(record)
+
+        expect(record.errors[:mrent]).not_to be_present
+        expect(record.errors[:type]).not_to be_present
+      end
+    end
+
+    context "when the type is blank" do
+      let(:record) { build(:sales_log, mrent: 100_000, ownershipsch: 1, type: nil) }
+
+      it "does not add an error" do
+        sale_information_validator.validate_basic_monthly_rent(record)
+
+        expect(record.errors[:mrent]).not_to be_present
+        expect(record.errors[:type]).not_to be_present
+      end
+    end
+
+    context "when higher than upper bound" do
+      let(:record) { build(:sales_log, mrent: 100_000, ownershipsch: 1, type: 2) }
+
+      it "adds an error" do
+        sale_information_validator.validate_basic_monthly_rent(record)
+
+        expect(record.errors[:mrent]).to include(I18n.t("validations.sale_information.monthly_rent.higher_than_expected"))
+        expect(record.errors[:type]).to include(I18n.t("validations.sale_information.monthly_rent.higher_than_expected"))
+      end
+    end
+  end
 end