diff --git a/src/blocker.rs b/src/blocker.rs
index e69c0583..78d7edd1 100644
--- a/src/blocker.rs
+++ b/src/blocker.rs
@@ -800,6 +800,7 @@ impl NetworkFilterList {
             };
 
             optimized.append(&mut unoptimizable);
+            optimized.shrink_to_fit();
             optimized_map.insert(key, optimized);
         }