diff --git a/src/impl/realm_coordinator.cpp b/src/impl/realm_coordinator.cpp
index 5b60ab4b..4425d2d3 100644
--- a/src/impl/realm_coordinator.cpp
+++ b/src/impl/realm_coordinator.cpp
@@ -331,8 +331,6 @@ void RealmCoordinator::run_async_notifiers()
         change_info.resize(1);
     }
     else {
-        change_info.resize(2);
-
         // Sort newly added notifiers by their source version so that we can pull them
         // all forward to the latest version in a single pass over the transaction log
         std::sort(new_notifiers.begin(), new_notifiers.end(),
@@ -340,6 +338,18 @@ void RealmCoordinator::run_async_notifiers()
         version = m_advancer_sg->get_version_of_current_transaction();
         REALM_ASSERT(version == new_notifiers.front()->version());
 
+        // Preallocate the required amount of space in the vector so that we can
+        // safely give out pointers to within the vector
+        {
+            size_t count = 2;
+            for (auto it = new_notifiers.begin(), next = it + 1; next != new_notifiers.end(); ++it, ++next) {
+                if ((*it)->version() != (*next)->version())
+                    ++count;
+            }
+            change_info.reserve(count);
+            change_info.resize(2);
+        }
+
         TransactionChangeInfo* info = &change_info.back();
 
         // Advance each of the new notifiers to the latest version, attaching them