diff --git a/src/func/classes/composition.rs b/src/func/classes/composition.rs
index 8ae9645..7a7c5ca 100644
--- a/src/func/classes/composition.rs
+++ b/src/func/classes/composition.rs
@@ -145,3 +145,23 @@ impl<U: LocalFunctor + Functor, V: LocalFunctor> LocalFunctor for CompositionCla
         U::stuff::<_, T>(U::fmap(V::stuff::<_, T>, fa))
     }
 }
+
+impl<U: SharedFunctor + Functor, V: SharedFunctor> SharedFunctor for CompositionClass<U, V> {
+    type Shared<'a, A: 'a + Clone> = U::Shared<'a, V::Shared<'a, A>>
+    where
+        Self: 'a;
+
+    fn share<'a, A: 'a + Clone>(fa: Self::F<'a, A>) -> Self::Shared<'a, A>
+    where
+        Self: 'a,
+    {
+        U::share(U::fmap(V::share, fa))
+    }
+
+    fn unshare<'a, A: 'a + Clone>(sa: Self::Shared<'a, A>) -> Self::F<'a, A>
+    where
+        Self: 'a,
+    {
+        U::fmap(V::unshare, U::unshare(sa))
+    }
+}