diff --git a/eth2/types/src/test_utils/testing_beacon_state_builder.rs b/eth2/types/src/test_utils/testing_beacon_state_builder.rs
index b3cfea6c0..e3f3313de 100644
--- a/eth2/types/src/test_utils/testing_beacon_state_builder.rs
+++ b/eth2/types/src/test_utils/testing_beacon_state_builder.rs
@@ -23,7 +23,7 @@ impl TestingBeaconStateBuilder {
             .collect();
 
         let validators = keypairs
-            .iter()
+            .par_iter()
             .map(|keypair| {
                 let withdrawal_credentials = Hash256::from_slice(&get_withdrawal_credentials(
                     &keypair.pk,