diff --git a/lib/hd/private.js b/lib/hd/private.js
index 3dfbeff2..1711b31f 100644
--- a/lib/hd/private.js
+++ b/lib/hd/private.js
@@ -199,7 +199,7 @@ HDPrivateKey.prototype.derive = function derive(index, hardened) {
   if (cache)
     return cache;
 
-  const bw = new StaticWriter(37);
+  const bw = StaticWriter.pool(37);
 
   if (index & common.HARDENED) {
     bw.writeU8(0);
diff --git a/lib/hd/public.js b/lib/hd/public.js
index b93feebd..e4928671 100644
--- a/lib/hd/public.js
+++ b/lib/hd/public.js
@@ -165,7 +165,7 @@ HDPublicKey.prototype.derive = function derive(index, hardened) {
   if (cache)
     return cache;
 
-  const bw = new StaticWriter(37);
+  const bw = StaticWriter.pool(37);
 
   bw.writeBytes(this.publicKey);
   bw.writeU32BE(index);