diff --git a/app/services/investment_service.py b/app/services/investment_service.py
index bd13255..154a32d 100644
--- a/app/services/investment_service.py
+++ b/app/services/investment_service.py
@@ -329,8 +329,10 @@ def get_portfolio_summary():
     Also returns per-account groups for investments that are linked to an account
     (e.g. separate Schwab Individual vs Roth IRA views).
     """
+    from sqlalchemy import func
     investments = Investment.query.filter_by(is_active=True).order_by(
-        Investment.account_id.asc().nullslast(),
+        func.isnull(Investment.account_id),   # 0 for linked, 1 for NULL → linked first
+        Investment.account_id,
         Investment.asset_type,
         Investment.asset_name,
     ).all()