diff --git a/sstables/m_format_read_helpers.cc b/sstables/m_format_read_helpers.cc
index 7a9f2981bc..6d4d8ed7de 100644
--- a/sstables/m_format_read_helpers.cc
+++ b/sstables/m_format_read_helpers.cc
@@ -58,4 +58,36 @@ future<int64_t> read_signed_vint(random_access_reader& in) {
     return read_vint_impl<int64_t>(in);
 }
 
+std::ostream& operator<<(std::ostream& out, sstables::bound_kind_m kind) {
+    switch (kind) {
+    case sstables::bound_kind_m::excl_end:
+        out << "excl_end";
+        break;
+    case sstables::bound_kind_m::incl_start:
+        out << "incl_start";
+        break;
+    case sstables::bound_kind_m::excl_end_incl_start:
+        out << "excl_end_incl_start";
+        break;
+    case sstables::bound_kind_m::static_clustering:
+        out << "static_clustering";
+        break;
+    case sstables::bound_kind_m::clustering:
+        out << "clustering";
+        break;
+    case sstables::bound_kind_m::incl_end_excl_start:
+        out << "incl_end_excl_start";
+        break;
+    case sstables::bound_kind_m::incl_end:
+        out << "incl_end";
+        break;
+    case sstables::bound_kind_m::excl_start:
+        out << "excl_start";
+        break;
+    default:
+        out << static_cast<unsigned>(kind);
+    }
+    return out;
+}
+
 }  // namespace sstables
diff --git a/sstables/m_format_read_helpers.hh b/sstables/m_format_read_helpers.hh
index 674a17ec3e..efddca3cc3 100644
--- a/sstables/m_format_read_helpers.hh
+++ b/sstables/m_format_read_helpers.hh
@@ -98,35 +98,3 @@ inline gc_clock::time_point parse_expiry(const serialization_header& header,
 }
 
 };   // namespace sstables
-
-inline std::ostream& operator<<(std::ostream& out, sstables::bound_kind_m kind) {
-    switch (kind) {
-    case sstables::bound_kind_m::excl_end:
-        out << "excl_end";
-        break;
-    case sstables::bound_kind_m::incl_start:
-        out << "incl_start";
-        break;
-    case sstables::bound_kind_m::excl_end_incl_start:
-        out << "excl_end_incl_start";
-        break;
-    case sstables::bound_kind_m::static_clustering:
-        out << "static_clustering";
-        break;
-    case sstables::bound_kind_m::clustering:
-        out << "clustering";
-        break;
-    case sstables::bound_kind_m::incl_end_excl_start:
-        out << "incl_end_excl_start";
-        break;
-    case sstables::bound_kind_m::incl_end:
-        out << "incl_end";
-        break;
-    case sstables::bound_kind_m::excl_start:
-        out << "excl_start";
-        break;
-    default:
-        out << static_cast<unsigned>(kind);
-    }
-    return out;
-}
diff --git a/sstables/mx/types.hh b/sstables/mx/types.hh
index f419d18481..91c59b6885 100644
--- a/sstables/mx/types.hh
+++ b/sstables/mx/types.hh
@@ -22,6 +22,7 @@
 #pragma once
 
 #include "clustering_bounds_comparator.hh"
+#include <iosfwd>
 
 namespace sstables {
 
@@ -94,4 +95,6 @@ inline bound_kind boundary_to_end_bound(bound_kind_m kind) {
     return (kind == bound_kind_m::incl_end_excl_start) ? bound_kind::incl_end : bound_kind::excl_end;
 }
 
+std::ostream& operator<<(std::ostream& out, sstables::bound_kind_m kind);
+
 }