diff --git a/app/services/merge/merge_organisations_service.rb b/app/services/merge/merge_organisations_service.rb
index 848efb13f..bcaad85a6 100644
--- a/app/services/merge/merge_organisations_service.rb
+++ b/app/services/merge/merge_organisations_service.rb
@@ -38,9 +38,7 @@ private
 
   def merge_rent_periods(merging_organisation)
     merging_organisation.rent_periods.each do |rent_period|
-      unless @absorbing_organisation.organisation_rent_periods.exists?(rent_period:)
-        @absorbing_organisation.organisation_rent_periods << OrganisationRentPeriod.new(rent_period:)
-      end
+      @absorbing_organisation.organisation_rent_periods << OrganisationRentPeriod.new(rent_period:) unless @absorbing_organisation.rent_periods.include?(rent_period)
     end
   end