diff --git a/py_hamt/store_httpx.py b/py_hamt/store_httpx.py
index 89b6c9b..a4bb45d 100644
--- a/py_hamt/store_httpx.py
+++ b/py_hamt/store_httpx.py
@@ -232,9 +232,21 @@ def __init__(
     # helper: get or create the client bound to the current running loop    #
     # --------------------------------------------------------------------- #
     def _loop_client(self) -> httpx.AsyncClient:
-        """Get or create a client for the current event loop."""
+        """Get or create a client for the current event loop.
+
+        If the instance was previously closed but owns its clients, a fresh
+        client mapping is lazily created on demand.  Users that supplied their
+        own ``httpx.AsyncClient`` still receive an error when the instance has
+        been closed, as we cannot safely recreate their client.
+        """
         if self._closed:
-            raise RuntimeError("KuboCAS is closed; create a new instance")
+            if not self._owns_client:
+                raise RuntimeError("KuboCAS is closed; create a new instance")
+            # We previously closed all internally-owned clients. Reset the
+            # state so that new clients can be created lazily.
+            self._closed = False
+            self._client_per_loop = {}
+
         loop: asyncio.AbstractEventLoop = asyncio.get_running_loop()
         try:
             return self._client_per_loop[loop]
@@ -245,7 +257,7 @@ def _loop_client(self) -> httpx.AsyncClient:
                 headers=self._default_headers,
                 auth=self._default_auth,
                 limits=httpx.Limits(max_connections=64, max_keepalive_connections=32),
-                # Uncomment when they finally support Robost HTTP/2 GOAWAY responses
+                # Uncomment when they finally support Robust HTTP/2 GOAWAY responses
                 # http2=True,
             )
             self._client_per_loop[loop] = client
diff --git a/tests/test_kubocas_session.py b/tests/test_kubocas_session.py
index 7e01938..bcc1c48 100644
--- a/tests/test_kubocas_session.py
+++ b/tests/test_kubocas_session.py
@@ -3,6 +3,7 @@
 import unittest
 from threading import Event, Thread
 
+import httpx
 import pytest
 
 from py_hamt import KuboCAS
@@ -189,18 +190,34 @@ def fake_run(coro):
 
 
 @pytest.mark.asyncio
-async def test_loop_client_raises_after_close():
-    """
-    Verify that calling _loop_client() on a closed KuboCAS instance
-    raises a RuntimeError.
-    """
-    # Arrange: Create a KuboCAS instance
+async def test_loop_client_reopens_after_close():
+    """Calling _loop_client() after aclose() recreates a fresh client."""
     cas = KuboCAS()
 
-    # Act: Close the instance. This should set the internal _closed flag.
+    first = cas._loop_client()
     await cas.aclose()
 
-    # Assert: Check that calling _loop_client again raises the expected error.
+    # Should no longer raise; instead a new client is created.
+    reopened = cas._loop_client()
+    assert isinstance(reopened, httpx.AsyncClient)
+    assert reopened is not first
+    assert cas._closed is False
+
+    await cas.aclose()
+
+
+@pytest.mark.asyncio
+async def test_loop_client_rejects_reuse_of_external_client(global_client_session):
+    """Calling _loop_client() after aclose() raises when client is user-supplied."""
+    cas = KuboCAS(
+        client=global_client_session,
+        rpc_base_url="http://127.0.0.1:5001",
+        gateway_base_url="http://127.0.0.1:8080",
+    )
+    assert cas._loop_client() is global_client_session
+
+    await cas.aclose()
+    cas._closed = True  # simulate closed instance with external client
     with pytest.raises(RuntimeError, match="KuboCAS is closed; create a new instance"):
         cas._loop_client()