diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 312f5d20d794f..0fc475cfa62ae 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -6017,7 +6017,7 @@ def __finalize__(self, other, method: str | None = None, **kwargs) -> Self:
                 object.__setattr__(self, name, getattr(other, name, None))
 
         if method == "concat":
-            objs = kwargs["objs"]
+            objs = other.objs
             # propagate attrs only if all concat arguments have the same attrs
             if all(bool(obj.attrs) for obj in objs):
                 # all concatenate arguments have non-empty attrs
diff --git a/pandas/core/reshape/concat.py b/pandas/core/reshape/concat.py
index 6381869c3e559..6836ba3f65691 100644
--- a/pandas/core/reshape/concat.py
+++ b/pandas/core/reshape/concat.py
@@ -5,6 +5,7 @@
 from __future__ import annotations
 
 from collections import abc
+import types
 from typing import (
     TYPE_CHECKING,
     Literal,
@@ -536,7 +537,9 @@ def _get_result(
 
             result = sample._constructor_from_mgr(mgr, axes=mgr.axes)
             result._name = name
-            return result.__finalize__(object(), method="concat", objs=objs)
+            return result.__finalize__(
+                types.SimpleNamespace(objs=objs), method="concat"
+            )
 
         # combine as columns in a frame
         else:
@@ -556,7 +559,7 @@ def _get_result(
             )
             df = cons(data, index=index, copy=False)
             df.columns = columns
-            return df.__finalize__(object(), method="concat", objs=objs)
+            return df.__finalize__(types.SimpleNamespace(objs=objs), method="concat")
 
     # combine block managers
     else:
@@ -595,7 +598,7 @@ def _get_result(
         )
 
         out = sample._constructor_from_mgr(new_data, axes=new_data.axes)
-        return out.__finalize__(object(), method="concat", objs=objs)
+        return out.__finalize__(types.SimpleNamespace(objs=objs), method="concat")
 
 
 def new_axes(
diff --git a/pandas/tests/generic/test_frame.py b/pandas/tests/generic/test_frame.py
index d06bfad930d7c..1d0f491529b56 100644
--- a/pandas/tests/generic/test_frame.py
+++ b/pandas/tests/generic/test_frame.py
@@ -84,9 +84,8 @@ def finalize(self, other, method=None, **kwargs):
                     value = getattr(left, name, "") + "|" + getattr(right, name, "")
                     object.__setattr__(self, name, value)
                 elif method == "concat":
-                    objs = kwargs["objs"]
                     value = "+".join(
-                        [getattr(o, name) for o in objs if getattr(o, name, None)]
+                        [getattr(o, name) for o in other.objs if getattr(o, name, None)]
                     )
                     object.__setattr__(self, name, value)
                 else:
diff --git a/pandas/tests/generic/test_series.py b/pandas/tests/generic/test_series.py
index 9e2dae8d132eb..7dcdcd96cce51 100644
--- a/pandas/tests/generic/test_series.py
+++ b/pandas/tests/generic/test_series.py
@@ -94,9 +94,12 @@ def test_metadata_propagation_indiv(self, monkeypatch):
         def finalize(self, other, method=None, **kwargs):
             for name in self._metadata:
                 if method == "concat" and name == "filename":
-                    objs = kwargs["objs"]
                     value = "+".join(
-                        [getattr(obj, name) for obj in objs if getattr(obj, name, None)]
+                        [
+                            getattr(obj, name)
+                            for obj in other.objs
+                            if getattr(obj, name, None)
+                        ]
                     )
                     object.__setattr__(self, name, value)
                 else: