diff --git a/apps/web/process/price/reactions/validation.ts b/apps/web/process/price/reactions/validation.ts
index d2547fa..476265d 100644
--- a/apps/web/process/price/reactions/validation.ts
+++ b/apps/web/process/price/reactions/validation.ts
@@ -61,4 +61,15 @@ export default function validationReactions({ store, apolloClient }: ReactionsCo
       });
     }
   );
+
+  reaction(
+    () => pick($calculation.$values.values, ['firstPaymentRub', 'subsidySum']),
+    ({ firstPaymentRub, subsidySum }) => {
+      $calculation.element('tbxFirstPaymentRub').validate({
+        invalid: firstPaymentRub - subsidySum < 0,
+        message:
+          'Первый платеж с учетом субсидии получается отрицательный, увеличьте первый платеж',
+      });
+    }
+  );
 }