diff --git a/crates/fidc-core/src/data.rs b/crates/fidc-core/src/data.rs
index f9661d5..c76847e 100644
--- a/crates/fidc-core/src/data.rs
+++ b/crates/fidc-core/src/data.rs
@@ -535,8 +535,11 @@ struct SymbolPriceSeries {
 }
 
 impl SymbolPriceSeries {
-    fn new(symbol: String, rows: &[DailyMarketSnapshot]) -> Self {
-        let mut sorted = rows.iter().collect::<Vec<_>>();
+    fn new<'a, I>(symbol: String, rows: I) -> Self
+    where
+        I: IntoIterator<Item = &'a DailyMarketSnapshot>,
+    {
+        let mut sorted = rows.into_iter().collect::<Vec<_>>();
         sorted.sort_by_key(|row| row.date);
 
         let dates = sorted.iter().map(|row| row.date).collect::<Vec<_>>();
@@ -3577,20 +3580,17 @@ mod optional_date_format {
 fn build_market_series(
     market_by_date: &BTreeMap<NaiveDate, Vec<DailyMarketSnapshot>>,
 ) -> HashMap<String, SymbolPriceSeries> {
-    let mut grouped = HashMap::<String, Vec<DailyMarketSnapshot>>::new();
+    let mut grouped = HashMap::<String, Vec<&DailyMarketSnapshot>>::new();
     for rows in market_by_date.values() {
         for row in rows {
-            grouped
-                .entry(row.symbol.clone())
-                .or_default()
-                .push(row.clone());
+            grouped.entry(row.symbol.clone()).or_default().push(row);
         }
     }
 
     grouped
         .into_iter()
         .map(|(symbol, rows)| {
-            let series = SymbolPriceSeries::new(symbol.clone(), &rows);
+            let series = SymbolPriceSeries::new(symbol.clone(), rows);
             (symbol, series)
         })
         .collect()