diff --git a/ibind/base/ws_client.py b/ibind/base/ws_client.py
index 9805445f..9da4e4a7 100644
--- a/ibind/base/ws_client.py
+++ b/ibind/base/ws_client.py
@@ -162,7 +162,14 @@ def _run_websocket(self, wsa: WebSocketApp):
 
         try:
             # the timeout is set to a little sooner than the interval
-            wsa.run_forever(ping_interval=self._ping_interval, ping_timeout=self._ping_interval * 0.95, sslopt=self._sslopt)
+            # skip_utf8_validation=True: IBKR occasionally emits non-UTF-8 bytes (e.g. 0x99) in text frames,
+            # which crashes the run_forever thread before on_close fires. Decoding is handled above this layer.
+            wsa.run_forever(
+                ping_interval=self._ping_interval,
+                ping_timeout=self._ping_interval * 0.95,
+                sslopt=self._sslopt,
+                skip_utf8_validation=True,
+            )
 
         except ValueError as e:
             if 'url is invalid' in str(e):
diff --git a/test/integration/base/test_websocket_client_i.py b/test/integration/base/test_websocket_client_i.py
index b14d5e75..40801dd2 100644
--- a/test/integration/base/test_websocket_client_i.py
+++ b/test/integration/base/test_websocket_client_i.py
@@ -95,6 +95,7 @@ def _verify_started(ws_client: WsClient, wsa_mock: MagicMock):
         sslopt=ws_client._sslopt,
         ping_interval=ws_client._ping_interval,
         ping_timeout=0.95 * ws_client._ping_interval,
+        skip_utf8_validation=True,
     )
     wsa_mock._on_open.assert_called_with(wsa_mock)
 
@@ -260,6 +261,7 @@ def run_forever_exception(
         sslopt: dict = None,
         ping_interval: float = 0,
         ping_timeout: Optional[float] = None,
+        skip_utf8_validation: bool = False,
     ):
         wsa_mock.run_forever.side_effect = old_run_forever
         raise RuntimeError(_ERROR_MESSAGE)
diff --git a/test/integration/base/websocketapp_mock.py b/test/integration/base/websocketapp_mock.py
index 5961f7a4..af2458c6 100644
--- a/test/integration/base/websocketapp_mock.py
+++ b/test/integration/base/websocketapp_mock.py
@@ -41,7 +41,7 @@ def close(wsa_mock: MagicMock, status: str = None):
     wsa_mock._on_close(wsa_mock, None, None)
 
 
-def run_forever(wsa_mock: MagicMock, sslopt: dict = None, ping_interval: float = 0, ping_timeout: Optional[float] = None):
+def run_forever(wsa_mock: MagicMock, sslopt: dict = None, ping_interval: float = 0, ping_timeout: Optional[float] = None, skip_utf8_validation: bool = False):
     wsa_mock.keep_running = True
     wsa_mock._on_open(wsa_mock)