diff --git a/include/xo/stringtable2/DUniqueString.hpp b/include/xo/stringtable2/DUniqueString.hpp
index 9f56a9c..9a4357e 100644
--- a/include/xo/stringtable2/DUniqueString.hpp
+++ b/include/xo/stringtable2/DUniqueString.hpp
@@ -55,6 +55,8 @@ namespace xo {
             /** not copyable **/
             DUniqueString(const DUniqueString &) = delete;
 
+            static constexpr bool is_gc_eligible() { return false; }
+
             ///@}
             /** @defgroup duniquestring-methods methods **/
             ///@{
diff --git a/include/xo/stringtable2/StringTable.hpp b/include/xo/stringtable2/StringTable.hpp
index 2a0d570..f7e0fc1 100644
--- a/include/xo/stringtable2/StringTable.hpp
+++ b/include/xo/stringtable2/StringTable.hpp
@@ -31,6 +31,9 @@ namespace xo {
             StringTable(size_type hint_max_capacity,
                         bool debug_flag = false);
 
+            /** false -> not eligible for GC (maps own memory + not moveable) **/
+            static constexpr bool is_gc_eligible() { return false; }
+
             /** lookup interned string; nullptr if not present **/
             const DUniqueString * lookup(std::string_view key) const;