diff --git a/CHANGELOG.md b/CHANGELOG.md
index 59728345..0faa432f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ### Unreleased
 
+* (patch) Reduce the number of object allocations the RSpec time tracker makes when adding `before/after(:all)` hooks time to test examples.
+
 ### 10.0.1
 
 * Add support for [File Paths Encryption](https://docs.knapsackpro.com/ruby/encryption/) to [Retry only Failures](https://docs.knapsackpro.com/ruby/retry-only-failures/).
diff --git a/lib/knapsack_pro/formatters/time_tracker.rb b/lib/knapsack_pro/formatters/time_tracker.rb
index 01baabd6..57d21aab 100644
--- a/lib/knapsack_pro/formatters/time_tracker.rb
+++ b/lib/knapsack_pro/formatters/time_tracker.rb
@@ -128,16 +128,27 @@ def top_level_group?(group)
       end
 
       def add_hooks_time(group, time_all_by_group_id_path)
-        group.each do |_, example|
+        return if time_all_by_group_id_path.empty?
+
+        # `group_id_path` without its trailing `]` is compared against every
+        # example of the group, so build it once instead of once per example.
+        hooks_time = time_all_by_group_id_path.map do |group_id_path, time|
+          [group_id_path, group_id_path[0..-2], time]
+        end
+
+        group.each_value do |example|
           next if example[:time_execution] == 0.0
 
-          example[:time_execution] += time_all_by_group_id_path.reduce(0.0) do |sum, (group_id_path, time)|
+          path = example[:path]
+          sum = 0.0
+          hooks_time.each do |group_id_path, group_id_path_prefix, time|
             # :path is a file path (a_spec.rb), sum any before/after(:all) in the file
-            next sum + time if group_id_path.start_with?(example[:path])
+            next sum += time if group_id_path.start_with?(path)
             # :path is an id path (a_spec.rb[1:1]), sum any before/after(:all) above it
-            next sum + time if example[:path].start_with?(group_id_path[0..-2])
-            sum
+            next sum += time if path.start_with?(group_id_path_prefix)
           end
+
+          example[:time_execution] += sum
         end
       end