diff --git a/src/groups/mqb/mqbblp/mqbblp_pushstream.t.cpp b/src/groups/mqb/mqbblp/mqbblp_pushstream.t.cpp
index 19f09b24f9..37137646ae 100644
--- a/src/groups/mqb/mqbblp/mqbblp_pushstream.t.cpp
+++ b/src/groups/mqb/mqbblp/mqbblp_pushstream.t.cpp
@@ -68,7 +68,8 @@ static void test2_iterations()
 
     // Imitate {m1, a1}, {m2, a2}, {m1, a2}, {m2, a1}
 
-    mqbblp::PushStream ps(bsl::nullptr_t(), s_allocator_p);
+    mqbblp::PushStream ps(bsl::optional<bdlma::ConcurrentPool*>(),
+                          s_allocator_p);
     unsigned int       subQueueId1 = 1;
     unsigned int       subQueueId2 = 2;