diff --git a/src/exchange/taler-exchange-httpd_db.c b/src/exchange/taler-exchange-httpd_db.c
index 0634e34f6..f53600cc1 100644
--- a/src/exchange/taler-exchange-httpd_db.c
+++ b/src/exchange/taler-exchange-httpd_db.c
@@ -2402,9 +2402,19 @@ TEH_DB_execute_payback (struct MHD_Connection *connection,
     return TEH_RESPONSE_reply_internal_db_error (connection,
 						 TALER_EC_PAYBACK_HISTORY_DB_ERROR);
   }
-  TALER_amount_subtract (&amount,
-                         value,
-                         &spent);
+  if (GNUNET_SYSERR ==
+      TALER_amount_subtract (&amount,
+                             value,
+                             &spent))
+  {
+    GNUNET_break (0);
+    TEH_plugin->rollback (TEH_plugin->cls,
+                          session);
+    TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
+                                            tl);
+    return TEH_RESPONSE_reply_internal_db_error (connection,
+						 TALER_EC_PAYBACK_COIN_BALANCE_NEGATIVE);
+  }
   if ( (0 == amount.fraction) &&
        (0 == amount.value) )
   {
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index 84240c295..bfca715a2 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -896,6 +896,13 @@ enum TALER_ErrorCode
    */
   TALER_EC_PAYBACK_BLINDING_FAILED = 1858,
 
+  /**
+   * The coin's remaining balance is zero.  The request is denied.
+   * This response is provided with an HTTP status code of
+   * MHD_HTTP_INTERNAL_SERVER_ERROR
+   */
+  TALER_EC_PAYBACK_COIN_BALANCE_NEGATIVE = 1857,
+
 
 
   /* *********** Merchant backend error codes ********* */