diff --git a/crates/trie/sparse/src/parallel.rs b/crates/trie/sparse/src/parallel.rs
index 8f83daa2d1..b8d413fb9d 100644
--- a/crates/trie/sparse/src/parallel.rs
+++ b/crates/trie/sparse/src/parallel.rs
@@ -999,6 +999,7 @@ impl SparseTrie for ParallelSparseTrie {
                 // Sync branch_node_masks with what's being committed to DB.
                 // This ensures that on subsequent root() calls, the masks reflect the actual
                 // DB state, which is needed for correct removal detection.
+                self.branch_node_masks.reserve(updates.updated_nodes.len());
                 for (path, node) in &updates.updated_nodes {
                     self.branch_node_masks.insert(
                         *path,
@@ -1854,6 +1855,9 @@ impl ParallelSparseTrie {
         update_actions: impl Iterator<Item = SparseTrieUpdatesAction>,
     ) {
         if let Some(updates) = self.updates.as_mut() {
+            let additional = update_actions.size_hint().0;
+            updates.updated_nodes.reserve(additional);
+            updates.removed_nodes.reserve(additional);
             for action in update_actions {
                 match action {
                     SparseTrieUpdatesAction::InsertRemoved(path) => {