diff --git a/beacon/sync/src/main/java/tech/pegasys/teku/beacon/sync/fetch/FetchBlobSidecarsTask.java b/beacon/sync/src/main/java/tech/pegasys/teku/beacon/sync/fetch/FetchBlobSidecarsTask.java
index a95fc06f734..28ed85a6d30 100644
--- a/beacon/sync/src/main/java/tech/pegasys/teku/beacon/sync/fetch/FetchBlobSidecarsTask.java
+++ b/beacon/sync/src/main/java/tech/pegasys/teku/beacon/sync/fetch/FetchBlobSidecarsTask.java
@@ -60,7 +60,7 @@ public Bytes32 getKey() {
 
   @Override
   SafeFuture<FetchResult<List<BlobSidecar>>> fetch(final Eth2Peer peer) {
-    final List<BlobSidecar> blobSidecars = new ArrayList<>();
+    final List<BlobSidecar> blobSidecars = new ArrayList<>(blobIdentifiers.size());
     return peer.requestBlobSidecarsByRoot(
             blobIdentifiers, RpcResponseListener.from(blobSidecars::add))
         .thenApply(__ -> FetchResult.createSuccessful(peer, blobSidecars))