diff --git a/tradingagents/graph/portfolio_analysis.py b/tradingagents/graph/portfolio_analysis.py
index cc7208ea..728985d8 100644
--- a/tradingagents/graph/portfolio_analysis.py
+++ b/tradingagents/graph/portfolio_analysis.py
@@ -186,6 +186,6 @@ class PortfolioAnalyzer:
             "portfolio_summary": portfolio_summary,
         }
 
-        log_file = directory / f"portfolio_analysis_{str(trade_date).replace('/', '-')}.json"
+        log_file = directory / f"portfolio_analysis_{re.sub(r'[^\w.-]', '_', str(trade_date))}.json"
         with log_file.open("w", encoding="utf-8") as f:
             json.dump(log_data, f, indent=4)