diff --git a/apps/api/src/controllers/facturacion.controller.ts b/apps/api/src/controllers/facturacion.controller.ts
index f866728..2f19dff 100644
--- a/apps/api/src/controllers/facturacion.controller.ts
+++ b/apps/api/src/controllers/facturacion.controller.ts
@@ -15,6 +15,7 @@ import { prisma } from '../config/database.js';
 import { AppError } from '../middlewares/error.middleware.js';
 import { hasPlatformRole } from '../utils/platform-admin.js';
 import { auditFromReq } from '../utils/audit.js';
+import { recomputarSaldoPendiente } from '../utils/saldo.js';
 
 function effectiveTenantId(req: Request): string {
   return req.viewingTenantId || req.user!.tenantId;
@@ -272,6 +273,11 @@ export async function emitir(req: Request, res: Response, next: NextFunction) {
       contribuyenteId ?? null, xmlString,
     ]);
 
+    // Inicializar saldo pendiente para I/PPD (igual que el flujo SAT)
+    if (parsed.tipoComprobante === 'I' && parsed.metodoPago === 'PPD' && parsed.uuid) {
+      await recomputarSaldoPendiente(pool, [parsed.uuid]);
+    }
+
     // Enviar por email si el receptor tiene email — ruteado a la org correcta
     const customerEmail = req.body.customer?.email;
     if (customerEmail) {
@@ -325,7 +331,7 @@ export async function cancelar(req: Request, res: Response, next: NextFunction)
   try {
     const tenantId = effectiveTenantId(req);
     const { uuid } = req.params;
-    const { motive, substitution } = req.body;
+    const { motive, substitution, contribuyenteId: bodyContribuyenteId } = req.body;
 
     const pool = req.tenantPool!;
     const { rows } = await pool.query(
@@ -340,6 +346,12 @@ export async function cancelar(req: Request, res: Response, next: NextFunction)
     const facturapiId = rows[0].facturapi_id;
     const cfdiContribuyenteId = rows[0].contribuyente_id as string | null;
 
+    // En modelo multi-contribuyente: si el caller envía un contribuyenteId,
+    // solo puede cancelar facturas de ESE contribuyente.
+    if (bodyContribuyenteId && cfdiContribuyenteId && bodyContribuyenteId !== cfdiContribuyenteId) {
+      return res.status(403).json({ message: 'No tienes permiso para cancelar esta factura' });
+    }
+
     const result = cfdiContribuyenteId
       ? await cancelInvoiceContribuyente(pool, cfdiContribuyenteId, facturapiId, motive || '02', substitution)
       : await facturapiService.cancelInvoice(tenantId, facturapiId, motive || '02', substitution);
diff --git a/apps/web/app/(dashboard)/cfdi/page.tsx b/apps/web/app/(dashboard)/cfdi/page.tsx
index 620fc92..14e839b 100644
--- a/apps/web/app/(dashboard)/cfdi/page.tsx
+++ b/apps/web/app/(dashboard)/cfdi/page.tsx
@@ -909,7 +909,7 @@ export default function CfdiPage() {
     }
     setCancelling(true);
     try {
-      await cancelarFactura(cancelTarget.uuid, cancelMotive, cancelMotive === '01' ? cancelSubstitution.trim() : undefined);
+      await cancelarFactura(cancelTarget.uuid, cancelMotive, cancelMotive === '01' ? cancelSubstitution.trim() : undefined, selectedContribuyenteId || undefined);
       await queryClient.invalidateQueries({ queryKey: ['cfdis'] });
       setCancelTarget(null);
       alert('Factura cancelada. El estatus final depende del SAT (puede quedar en "pendiente" si requiere aceptación del receptor).');
@@ -2087,6 +2087,9 @@ export default function CfdiPage() {
                           <td className="py-3">
                             <div className="flex items-center gap-0">
                               {(cfdi as any).source === 'facturapi' && (cfdi.status === 'Vigente' || cfdi.status === '1') && (
+                                // Solo el contribuyente emisor puede cancelar su propia factura
+                                ((!selectedContribuyenteId && !cfdi.contribuyenteId) ||
+                                  (selectedContribuyenteId && cfdi.contribuyenteId === selectedContribuyenteId)) && (
                                 <Button
                                   variant="ghost"
                                   size="icon"
@@ -2096,7 +2099,7 @@ export default function CfdiPage() {
                                 >
                                   <XCircle className="h-4 w-4" />
                                 </Button>
-                              )}
+                              ))}
                               <Button
                               variant="ghost"
                               size="icon"
diff --git a/apps/web/lib/api/facturacion.ts b/apps/web/lib/api/facturacion.ts
index d509cb3..9ba5b2a 100644
--- a/apps/web/lib/api/facturacion.ts
+++ b/apps/web/lib/api/facturacion.ts
@@ -112,8 +112,8 @@ export const updatePaqueteCatalogo = (id: number, data: { precio?: number; activ
   apiClient.put<PaqueteCatalogoAdmin>(`/facturacion/timbres/paquetes-catalogo/${id}`, data).then(r => r.data);
 export const emitirFactura = (data: InvoiceData) =>
   apiClient.post<InvoiceResult>('/facturacion/emitir', data).then(r => r.data);
-export const cancelarFactura = (uuid: string, motive?: string, substitution?: string) =>
-  apiClient.post(`/facturacion/cancelar/${uuid}`, { motive, substitution }).then(r => r.data);
+export const cancelarFactura = (uuid: string, motive?: string, substitution?: string, contribuyenteId?: string) =>
+  apiClient.post(`/facturacion/cancelar/${uuid}`, { motive, substitution, contribuyenteId }).then(r => r.data);
 export const downloadPdf = (id: string) =>
   apiClient.get(`/facturacion/pdf/${id}`, { responseType: 'blob' }).then(r => r.data);
 export const downloadXml = (id: string) =>