diff --git a/supabase/functions/seed-test-data/index.ts b/supabase/functions/seed-test-data/index.ts
index 147db1e2..53413da8 100644
--- a/supabase/functions/seed-test-data/index.ts
+++ b/supabase/functions/seed-test-data/index.ts
@@ -334,10 +334,21 @@ Deno.serve(async (req) => {
       return { submissionId, itemId, typeId: null };
     }
 
+    // Helper function to properly pluralize company types
+    const pluralizeCompanyType = (singular: string): string => {
+      const pluralMap: Record<string, string> = {
+        'manufacturer': 'manufacturers',
+        'operator': 'operators',
+        'designer': 'designers',
+        'property_owner': 'property_owners'
+      };
+      return pluralMap[singular] || singular + 's';
+    };
+
     // Create companies FIRST so parks can reference operators/owners
     const companyTypes = ['manufacturer', 'operator', 'designer', 'property_owner'];
     for (const compType of companyTypes) {
-      if (entityTypes.includes(compType + 's') || entityTypes.includes(compType === 'manufacturer' ? 'manufacturers' : compType === 'property_owner' ? 'property_owners' : compType + 's')) {
+      if (entityTypes.includes(pluralizeCompanyType(compType))) {
         const count = Math.floor(plan.companies / 4);
         for (let i = 0; i < count; i++) {
           const level = getPopulationLevel(fieldDensity, i);