diff --git a/db/README.md b/db/README.md
index ccc0068..59d5e01 100644
--- a/db/README.md
+++ b/db/README.md
@@ -11,6 +11,7 @@
 7. `db/migrations/0007_phase1_excel_webhook.sql`
 8. `db/migrations/0008_shopify_sync_technical.sql`
 9. `db/migrations/0013_virtual_shortage_lot_allocations.sql`
+10. `db/migrations/0014_require_human_lot_activation.sql`
 
 ## Beispielausfuehrung
 
diff --git a/db/migrations/0014_require_human_lot_activation.sql b/db/migrations/0014_require_human_lot_activation.sql
new file mode 100644
index 0000000..84f5ce4
--- /dev/null
+++ b/db/migrations/0014_require_human_lot_activation.sql
@@ -0,0 +1,87 @@
+-- Never promote an unnamed placeholder lot automatically.
+
+CREATE OR REPLACE FUNCTION fn_auto_switch_lot_when_depleted()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  v_product_id BIGINT;
+  v_open_lot_id BIGINT;
+  v_current_net NUMERIC;
+  v_event_key TEXT;
+BEGIN
+  SELECT product_id
+  INTO v_product_id
+  FROM stock_lot
+  WHERE id = NEW.lot_id;
+
+  IF NOT EXISTS (
+    SELECT 1 FROM stock_lot WHERE id = NEW.lot_id AND status = 'current'
+  ) THEN
+    RETURN NEW;
+  END IF;
+
+  SELECT qty_net
+  INTO v_current_net
+  FROM v_stock_lot_balance
+  WHERE stock_lot_id = NEW.lot_id;
+
+  IF COALESCE(v_current_net, 0) > 0 THEN
+    RETURN NEW;
+  END IF;
+
+  PERFORM 1
+  FROM stock_lot
+  WHERE product_id = v_product_id
+  FOR UPDATE;
+
+  IF NOT EXISTS (
+    SELECT 1 FROM stock_lot WHERE id = NEW.lot_id AND status = 'current'
+  ) THEN
+    RETURN NEW;
+  END IF;
+
+  SELECT id
+  INTO v_open_lot_id
+  FROM stock_lot
+  WHERE product_id = v_product_id
+    AND status = 'open'
+    AND lot_number IS NOT NULL
+  ORDER BY id
+  LIMIT 1
+  FOR UPDATE;
+
+  -- A real lot must be activated by a human through the lot-management flow.
+  IF v_open_lot_id IS NULL THEN
+    RETURN NEW;
+  END IF;
+
+  UPDATE stock_lot
+  SET status = 'closed', updated_at = NOW()
+  WHERE id = NEW.lot_id;
+
+  UPDATE stock_lot
+  SET status = 'current', updated_at = NOW()
+  WHERE id = v_open_lot_id;
+
+  INSERT INTO stock_lot (product_id, lot_number, status)
+  VALUES (v_product_id, NULL, 'open');
+
+  v_event_key := format('lot.auto_switched:%s:%s', v_product_id, txid_current());
+
+  PERFORM fn_enqueue_event(
+    'lot.auto_switched',
+    v_event_key,
+    'stock_lot',
+    NEW.lot_id::TEXT,
+    jsonb_build_object(
+      'productId', v_product_id,
+      'closedLotId', NEW.lot_id,
+      'newCurrentLotId', v_open_lot_id,
+      'occurredAt', NOW()
+    )
+  );
+
+  RETURN NEW;
+END;
+$$;
diff --git a/modules/erp/lager/service.php b/modules/erp/lager/service.php
index 2e100ca..7900848 100644
--- a/modules/erp/lager/service.php
+++ b/modules/erp/lager/service.php
@@ -193,6 +193,7 @@ function switch_current_lot(PDO $pdo, int $productId, int $oldCurrentLotId, int
          FROM stock_lot
          WHERE product_id = :product_id
            AND status = 'open'
+           AND lot_number IS NOT NULL
          ORDER BY id
          LIMIT 1
          FOR UPDATE"