diff --git a/models/api/finstitutions/trading/symbols/list.py b/models/api/finstitutions/trading/symbols/list.py
index d6cf72d..646be78 100644
--- a/models/api/finstitutions/trading/symbols/list.py
+++ b/models/api/finstitutions/trading/symbols/list.py
@@ -173,12 +173,15 @@ class TradingSymbolListRequestData(BaseModel):
 
     @field_validator("exchanges", mode = "before")
     def ensure_list(cls, value):
-        _exchg = []
         if isinstance(value, str):
-            if regex.match(text = value, pattern = r"\[.*\]"): _exchg = json.from_string(value)
-            else: _exchg.append(value)
-        elif isinstance(value, list):
-            _exchg = value
+            if regex.match(
+                    text = value,
+                    pattern = r"\[.*\]",
+                    dot_all = True
+            ): value = json.from_string(value)
+            else: value = [value]
+        elif isinstance(value, list): pass
+        else: value = None
         return value