diff --git a/src/zai/core/_http_client.py b/src/zai/core/_http_client.py
index 080f8b2..706a50a 100644
--- a/src/zai/core/_http_client.py
+++ b/src/zai/core/_http_client.py
@@ -464,6 +464,26 @@ def _process_response_data(
 	def _should_stream_response_body(self, request: httpx.Request) -> bool:
 		return request.headers.get(RAW_RESPONSE_HEADER) == 'stream'  # type: ignore[no-any-return]
 
+	def _business_error_code(self, response: httpx.Response) -> str | None:
+		try:
+			payload = response.json()
+		except httpx.ResponseNotRead:
+			try:
+				response.read()
+				payload = response.json()
+			except (httpx.HTTPError, ValueError):
+				return None
+		except ValueError:
+			return None
+
+		if not isinstance(payload, Mapping):
+			return None
+		error = payload.get('error')
+		if not isinstance(error, Mapping):
+			return None
+		code = error.get('code')
+		return str(code) if code is not None else None
+
 	def _should_retry(self, response: httpx.Response) -> bool:
 		# Note: this is not a standard header
 		should_retry_header = response.headers.get('x-should-retry')
@@ -488,6 +508,11 @@ def _should_retry(self, response: httpx.Response) -> bool:
 
 		# Retry on rate limits.
 		if response.status_code == 429:
+			# Business error 1113 requires an account recharge; retrying the same
+			# request cannot succeed without an external account-state change.
+			if self._business_error_code(response) == '1113':
+				log.debug('Not retrying HTTP 429 with non-retryable business error 1113')
+				return False
 			log.debug('Retrying due to status code %i', response.status_code)
 			return True
 
diff --git a/tests/unit_tests/test_retry_policy.py b/tests/unit_tests/test_retry_policy.py
new file mode 100644
index 0000000..9a252e1
--- /dev/null
+++ b/tests/unit_tests/test_retry_policy.py
@@ -0,0 +1,93 @@
+from __future__ import annotations
+
+import httpx
+import pytest
+from zai.core import APIReachLimitError
+from zai.core._constants import ZAI_DEFAULT_TIMEOUT
+from zai.core._http_client import HttpClient
+from zai.core._streaming import StreamResponse
+
+
+def make_client(http_client: httpx.Client | None = None, max_retries: int = 3) -> HttpClient:
+	return HttpClient(
+		version='test-version',
+		base_url='https://api.test.com',
+		_strict_response_validation=False,
+		max_retries=max_retries,
+		timeout=ZAI_DEFAULT_TIMEOUT,
+		custom_httpx_client=http_client,
+	)
+
+
+def test_http_429_arrears_is_not_retried() -> None:
+	attempts = 0
+
+	def handler(request: httpx.Request) -> httpx.Response:
+		nonlocal attempts
+		attempts += 1
+		return httpx.Response(
+			429,
+			json={'error': {'code': '1113', 'message': 'Account in arrears'}},
+			request=request,
+		)
+
+	with httpx.Client(transport=httpx.MockTransport(handler)) as http_client:
+		client = make_client(http_client=http_client)
+		with pytest.raises(APIReachLimitError):
+			client.get('/resource', cast_type=dict)
+
+	assert attempts == 1
+
+
+@pytest.mark.parametrize('code', ['1305', 1305])
+def test_http_429_rate_limit_remains_retryable(code: str | int) -> None:
+	client = make_client()
+	try:
+		response = httpx.Response(429, json={'error': {'code': code, 'message': 'Rate limited'}})
+		assert client._should_retry(response) is True
+	finally:
+		client.close()
+
+
+def test_http_429_unknown_payload_remains_retryable() -> None:
+	client = make_client()
+	try:
+		response = httpx.Response(429, content=b'not-json')
+		assert client._should_retry(response) is True
+	finally:
+		client.close()
+
+
+@pytest.mark.parametrize(('header', 'expected'), [('true', True), ('false', False)])
+def test_explicit_retry_header_takes_precedence_for_arrears(header: str, expected: bool) -> None:
+	client = make_client()
+	try:
+		response = httpx.Response(
+			429,
+			headers={'x-should-retry': header},
+			json={'error': {'code': '1113', 'message': 'Account in arrears'}},
+		)
+		assert client._should_retry(response) is expected
+	finally:
+		client.close()
+
+
+def test_streamed_http_429_arrears_is_not_retried() -> None:
+	attempts = 0
+
+	def handler(request: httpx.Request) -> httpx.Response:
+		nonlocal attempts
+		attempts += 1
+		return httpx.Response(
+			429,
+			request=request,
+			stream=httpx.ByteStream(b'{"error":{"code":"1113","message":"Account in arrears"}}'),
+		)
+
+	with httpx.Client(transport=httpx.MockTransport(handler)) as http_client:
+		client = make_client(http_client=http_client)
+		with pytest.raises(APIReachLimitError) as exc_info:
+			client.get('/resource', cast_type=dict, stream=True, stream_cls=StreamResponse)
+
+	assert attempts == 1
+	assert exc_info.value.response.json()['error']['code'] == '1113'