diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index 8a1927a39ca..79726b0ceb4 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -1,5 +1,7 @@
 ### SDK Features
 
 ### SDK Enhancements
+* `service/glacier`: Improve efficiency of tree hash algorithm
+  * Refactor tree hashing to reduce allocations.
 
 ### SDK Bugs