diff --git a/crates/fidc-core/src/data.rs b/crates/fidc-core/src/data.rs
index 9534b6c..8c1b639 100644
--- a/crates/fidc-core/src/data.rs
+++ b/crates/fidc-core/src/data.rs
@@ -1304,10 +1304,11 @@ impl DataSet {
         sort_groups_by_symbol(&mut factor_by_date, |item| item.symbol.as_str());
         let mut market_rows_by_symbol = AHashMap::<String, Vec<&DailyMarketSnapshot>>::new();
         for row in market_by_date.values().flatten() {
-            market_rows_by_symbol
-                .entry(row.symbol.clone())
-                .or_default()
-                .push(row);
+            if let Some(rows) = market_rows_by_symbol.get_mut(row.symbol.as_str()) {
+                rows.push(row);
+                continue;
+            }
+            market_rows_by_symbol.insert(row.symbol.clone(), vec![row]);
         }
         let market_rows_by_symbol = market_rows_by_symbol.into_iter().collect::<Vec<_>>();
         let market_series_by_symbol = market_rows_by_symbol