diff --git a/src/data_stream.py b/src/data_stream.py
index 46117ae..a5c2509 100644
--- a/src/data_stream.py
+++ b/src/data_stream.py
@@ -48,14 +48,10 @@ class KlineStream:
     async def _preload_history(self, client: AsyncClient, limit: int = 200):
         """REST API로 과거 캔들 데이터를 버퍼에 미리 채운다."""
         logger.info(f"과거 캔들 {limit}개 로드 중...")
-        loop = asyncio.get_event_loop()
-        klines = await loop.run_in_executor(
-            None,
-            lambda: client.futures_klines(
-                symbol=self.symbol.upper(),
-                interval=self.interval,
-                limit=limit,
-            ),
+        klines = await client.futures_klines(
+            symbol=self.symbol.upper(),
+            interval=self.interval,
+            limit=limit,
         )
         # 마지막 캔들은 아직 닫히지 않았을 수 있으므로 제외
         for k in klines[:-1]:
diff --git a/tests/test_data_stream.py b/tests/test_data_stream.py
index 82a6fa0..26b2ed4 100644
--- a/tests/test_data_stream.py
+++ b/tests/test_data_stream.py
@@ -57,7 +57,7 @@ async def test_preload_history_fills_buffer():
         for i in range(201)  # 201개 반환 → 마지막 1개 제외 → 200개 버퍼
     ]
 
-    mock_client = MagicMock()
+    mock_client = AsyncMock()
     mock_client.futures_klines.return_value = fake_klines
 
     await stream._preload_history(mock_client, limit=200)