diff --git a/crates/fidc-core/src/data.rs b/crates/fidc-core/src/data.rs
index 177e41b..65dbcd2 100644
--- a/crates/fidc-core/src/data.rs
+++ b/crates/fidc-core/src/data.rs
@@ -5093,6 +5093,15 @@ mod tests {
         )
         .unwrap();
 
+        let lexical_symbols = ["000001.SZ", "000300.SH", "600000.SH"];
+        let lexical_symbol_ids = lexical_symbols.map(|symbol| data.symbol_id(symbol).unwrap());
+        assert!(
+            lexical_symbol_ids
+                .windows(2)
+                .all(|window| window[0] < window[1]),
+            "symbol ids are the stable lexical tie-break key"
+        );
+
         for symbol in ["000001.SZ", "600000.SH"] {
             let symbol_id = data.symbol_id(symbol).unwrap();
             let day = data.daily_snapshot_view(date);
diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index b477003..1da72eb 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -10301,15 +10301,7 @@ impl PlatformExprStrategy {
                         .unwrap_or(std::cmp::Ordering::Equal)
                 };
                 if ordering == std::cmp::Ordering::Equal {
-                    let lhs_symbol = &universe_factor_day
-                        .factor(lhs.0)
-                        .expect("ranked candidate references missing factor row")
-                        .symbol;
-                    let rhs_symbol = &universe_factor_day
-                        .factor(rhs.0)
-                        .expect("ranked candidate references missing factor row")
-                        .symbol;
-                    lhs_symbol.cmp(rhs_symbol)
+                    lhs.0.cmp(&rhs.0)
                 } else {
                     ordering
                 }
@@ -11028,15 +11020,7 @@ impl PlatformExprStrategy {
                     .unwrap_or(std::cmp::Ordering::Equal)
             };
             if ordering == std::cmp::Ordering::Equal {
-                let lhs_symbol = &universe_factor_day
-                    .factor(lhs.0)
-                    .expect("quote-plan candidate references missing factor row")
-                    .symbol;
-                let rhs_symbol = &universe_factor_day
-                    .factor(rhs.0)
-                    .expect("quote-plan candidate references missing factor row")
-                    .symbol;
-                lhs_symbol.cmp(rhs_symbol)
+                lhs.0.cmp(&rhs.0)
             } else {
                 ordering
             }