diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index 98837eb..fde2659 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -556,6 +556,7 @@ pub struct PlatformExprStrategy {
     selection_quote_usage: StockFilterQuoteUsage,
     stock_rolling_requirements: StockRollingRequirements,
     stock_extra_factors_required: bool,
+    stock_extra_factor_identifiers: BTreeSet<String>,
     stock_text_factors_required: bool,
     stock_state_cache_date: RefCell<Option<NaiveDate>>,
     stock_state_cache: RefCell<
@@ -657,6 +658,11 @@ impl PlatformExprStrategy {
             &normalized_stock_filter_expr,
             &prelude_declared_identifiers,
         );
+        let stock_extra_factor_identifiers = Self::stock_extra_factor_identifiers_for_config(
+            &config,
+            &normalized_stock_filter_expr,
+            &prelude_declared_identifiers,
+        );
         let stock_text_factors_required = Self::stock_text_factors_required_for_config(
             &config,
             &normalized_stock_filter_expr,
@@ -681,6 +687,7 @@ impl PlatformExprStrategy {
             selection_quote_usage,
             stock_rolling_requirements,
             stock_extra_factors_required,
+            stock_extra_factor_identifiers,
             stock_text_factors_required,
             stock_state_cache_date: RefCell::new(None),
             stock_state_cache: RefCell::new(HashMap::new()),
@@ -3196,7 +3203,9 @@ impl PlatformExprStrategy {
             for identifier in Self::extract_identifier_candidates(&expanded_expr) {
                 if Self::is_reserved_scope_name(identifier.as_str())
                     || self.prelude_declared_identifiers.contains(&identifier)
-                    || (!day.available_factor_names.contains(&identifier)
+                    || (!self.stock_extra_factor_identifiers.contains(&identifier)
+                        && !item.extra_factors.contains_key(&identifier)
+                        && !day.available_factor_names.contains(&identifier)
                         && !day.available_text_factor_names.contains(&identifier))
                 {
                     continue;
@@ -3204,7 +3213,7 @@ impl PlatformExprStrategy {
                 if let Some(value) = item.extra_text_factors.get(&identifier) {
                     scope.push_dynamic(identifier, Dynamic::from(value.clone()));
                 } else {
-                    let value = item.extra_factors.get(&identifier).copied().unwrap_or(0.0);
+                    let value = item.extra_factors.get(&identifier).copied().unwrap_or(f64::NAN);
                     scope.push_dynamic(identifier, Dynamic::from(value));
                 }
             }
@@ -6423,6 +6432,69 @@ impl PlatformExprStrategy {
         })
     }
 
+    fn stock_extra_factor_identifiers_for_config(
+        config: &PlatformExprStrategyConfig,
+        normalized_stock_filter_expr: &str,
+        prelude_declared_identifiers: &BTreeSet<String>,
+    ) -> BTreeSet<String> {
+        let mut identifiers = BTreeSet::new();
+        if Self::stock_field_may_use_extra_factors(&config.market_cap_field) {
+            identifiers.insert(config.market_cap_field.trim().to_string());
+        }
+        if Self::stock_field_may_use_extra_factors(&config.rank_by) {
+            identifiers.insert(config.rank_by.trim().to_string());
+        }
+        let stock_filter_has_fast_path =
+            Self::stock_filter_fast_path_supported(normalized_stock_filter_expr);
+        if !stock_filter_has_fast_path {
+            Self::collect_stock_extra_factor_identifiers(
+                &mut identifiers,
+                &config.stock_filter_expr,
+                prelude_declared_identifiers,
+                true,
+            );
+        }
+        for expr in [
+            config.buy_scale_expr.as_str(),
+            config.stop_loss_expr.as_str(),
+            config.take_profit_expr.as_str(),
+            config.rank_expr.as_str(),
+        ] {
+            Self::collect_stock_extra_factor_identifiers(
+                &mut identifiers,
+                expr,
+                prelude_declared_identifiers,
+                true,
+            );
+        }
+        identifiers
+    }
+
+    fn collect_stock_extra_factor_identifiers(
+        out: &mut BTreeSet<String>,
+        expr: &str,
+        prelude_declared_identifiers: &BTreeSet<String>,
+        stock_rolling_helpers_require_extra: bool,
+    ) {
+        let normalized = Self::normalize_expr(expr);
+        for name in Self::extract_identifier_candidates(&normalized) {
+            if Self::is_expression_keyword(&name)
+                || Self::is_runtime_helper(&name)
+                || Self::is_reserved_scope_name(&name)
+                || Self::stock_field_is_builtin(&name)
+                || prelude_declared_identifiers.contains(&name)
+            {
+                continue;
+            }
+            if stock_rolling_helpers_require_extra
+                && matches!(name.as_str(), "rolling_mean" | "sma" | "ma" | "vma")
+            {
+                continue;
+            }
+            out.insert(name);
+        }
+    }
+
     fn stock_text_factors_required_for_config(
         config: &PlatformExprStrategyConfig,
         normalized_stock_filter_expr: &str,
@@ -8213,6 +8285,19 @@ mod tests {
         assert!((strategy.buy_commission(1_000.0) - 5.0).abs() < 1e-9);
     }
 
+    #[test]
+    fn platform_expr_tracks_requested_dynamic_factor_identifiers() {
+        let mut cfg = PlatformExprStrategyConfig::microcap_rotation();
+        cfg.rank_expr = "model_score + close / prev_close".to_string();
+
+        let strategy = PlatformExprStrategy::new(cfg);
+
+        assert!(strategy.stock_extra_factors_required);
+        assert!(strategy.stock_extra_factor_identifiers.contains("model_score"));
+        assert!(!strategy.stock_extra_factor_identifiers.contains("close"));
+        assert!(!strategy.stock_extra_factor_identifiers.contains("prev_close"));
+    }
+
     #[test]
     fn platform_expr_rewrites_prelude_assignment_ternary() {
         let prelude = "let cap_low = sig_close <= 0 ? 7 : max(5, min(cap_low_raw, 70));";