diff --git a/apps/api/src/services/regimen.service.ts b/apps/api/src/services/regimen.service.ts
index eb752fe..2fa98fb 100644
--- a/apps/api/src/services/regimen.service.ts
+++ b/apps/api/src/services/regimen.service.ts
@@ -64,7 +64,24 @@ export async function getRegimenesActivosClavesEfectivos(
     if (rows.length > 0 && rows[0].regimen_fiscal) {
       return rows[0].regimen_fiscal.split(',').map((c: string) => c.trim()).filter(Boolean);
     }
-    return [];
+    // Fallback: si el contribuyente no tiene regimen_fiscal, usamos los del tenant
+    // para no perder la alerta si el campo quedó vacío accidentalmente.
+    const tenantRegimenes = await getRegimenesActivosClaves(tenantId);
+    if (tenantRegimenes.length > 0) return tenantRegimenes;
+
+    const { rows: allRows } = await pool.query(
+      `SELECT DISTINCT regimen_fiscal FROM contribuyentes WHERE regimen_fiscal IS NOT NULL AND regimen_fiscal <> ''`,
+    );
+    const set = new Set<string>();
+    for (const row of allRows) {
+      if (row.regimen_fiscal) {
+        for (const clave of row.regimen_fiscal.split(',')) {
+          const trimmed = clave.trim();
+          if (trimmed) set.add(trimmed);
+        }
+      }
+    }
+    return Array.from(set);
   }
 
   const tenantRegimenes = await getRegimenesActivosClaves(tenantId);