diff --git a/stock/analysis/Common.py b/stock/analysis/Common.py
index 9f4fa9e..79f36b9 100644
--- a/stock/analysis/Common.py
+++ b/stock/analysis/Common.py
@@ -574,6 +574,9 @@ class Common:
 
     def check_optimal_buy_timeing(self, stock):
 
+        if stock['slow_k'][0] is None:
+            return False
+
         max_vol_5 = max(stock['volume'][0: 4])
         max_vol_30 = max(stock['volume'][4: 24])
         if max_vol_30 < max_vol_5: