diff --git a/app/services/bulk_upload/sales/year2023/row_parser.rb b/app/services/bulk_upload/sales/year2023/row_parser.rb
index 88815a089..925195ec3 100644
--- a/app/services/bulk_upload/sales/year2023/row_parser.rb
+++ b/app/services/bulk_upload/sales/year2023/row_parser.rb
@@ -425,6 +425,14 @@ class BulkUpload::Sales::Year2023::RowParser
             },
             on: :before_log
 
+  validates :field_105,
+            inclusion: {
+              in: [1, 2],
+              if: proc { field_89.present? && field_89 != 100 && shared_ownership? },
+              question: QUESTIONS[:field_105],
+            },
+            on: :before_log
+
   validates :field_13,
             presence: {
               message: I18n.t("validations.not_answered", question: "buyers living in property"),
@@ -1336,7 +1344,6 @@ private
 
   def validate_mortgageused
     if mortgageused.present? && mortgageused.to_i != 1 && mortgageused.to_i != 2
-      errors.add(:field_105, I18n.t("validations.invalid_option", question: "Was a mortgage used for the purchase of this property? - Shared ownership")) if shared_ownership?
       errors.add(:field_119, I18n.t("validations.invalid_option", question: "Was a mortgage used for the purchase of this property? - Discounted ownership")) if discounted_ownership?
       errors.add(:field_128, I18n.t("validations.invalid_option", question: "Was a mortgage used for the purchase of this property? - Outright sale")) if outright_sale?
     end
diff --git a/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb b/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
index be8a401cb..b9f95b181 100644
--- a/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
+++ b/spec/services/bulk_upload/sales/year2023/row_parser_spec.rb
@@ -1029,6 +1029,30 @@ RSpec.describe BulkUpload::Sales::Year2023::RowParser do
         expect(parser.errors[:field_119]).to be_empty
         expect(parser.errors[:field_128]).to be_empty
       end
+
+      context "when invalid value" do
+        let(:attributes) { setup_section_params.merge(field_105: "4") }
+
+        it "returns correct errors" do
+          expect(parser.errors[:field_105]).to include("Enter a valid value for Was a mortgage used for the purchase of this property? - Shared ownership")
+        end
+      end
+
+      context "when value is 3 and stairowned is not 100" do
+        let(:attributes) { setup_section_params.merge(field_105: "3", field_87: "1", field_88: "50", field_89: "99", field_111: nil) }
+
+        it "returns correct errors" do
+          expect(parser.errors[:field_105]).to include("Enter a valid value for Was a mortgage used for the purchase of this property? - Shared ownership")
+        end
+      end
+
+      context "when value is 3 and stairowned is not answered" do
+        let(:attributes) { setup_section_params.merge(field_105: "3", field_87: "1", field_88: "50", field_89: nil, field_111: nil) }
+
+        it "does not add errors" do
+          expect(parser.errors[:field_105]).not_to include("Enter a valid value for Was a mortgage used for the purchase of this property? - Shared ownership")
+        end
+      end
     end
 
     describe "#field_119" do