diff --git a/src/rapids_pre_commit_hooks/alpha_spec.py b/src/rapids_pre_commit_hooks/alpha_spec.py
index 1e5db98..de90d63 100644
--- a/src/rapids_pre_commit_hooks/alpha_spec.py
+++ b/src/rapids_pre_commit_hooks/alpha_spec.py
@@ -117,7 +117,8 @@ def create_specifier_string(specifiers):
                 else None
             )
             if anchor not in used_anchors:
-                used_anchors.add(anchor)
+                if anchor is not None:
+                    used_anchors.add(anchor)
                 has_alpha_spec = any(str(s) == ALPHA_SPECIFIER for s in req.specifier)
                 if args.mode == "development" and not has_alpha_spec:
                     linter.add_warning(
diff --git a/test/rapids_pre_commit_hooks/test_alpha_spec.py b/test/rapids_pre_commit_hooks/test_alpha_spec.py
index e06bfb4..ddcd685 100644
--- a/test/rapids_pre_commit_hooks/test_alpha_spec.py
+++ b/test/rapids_pre_commit_hooks/test_alpha_spec.py
@@ -139,6 +139,8 @@ def test_check_package_spec_anchor():
         """\
         - &cudf cudf>=24.04,<24.06
         - *cudf
+        - cuml>=24.04,<24.06
+        - rmm>=24.04,<24.06
         """
     )
     args = Mock(mode="development")
@@ -160,12 +162,31 @@ def test_check_package_spec_anchor():
     )
     assert linter.warnings == expected_linter.warnings
     assert used_anchors == {"cudf"}
+
     alpha_spec.check_package_spec(
         linter, args, loader.document_anchors[0], used_anchors, composed.value[1]
     )
     assert linter.warnings == expected_linter.warnings
     assert used_anchors == {"cudf"}
 
+    expected_linter.add_warning(
+        (37, 55), "add alpha spec for RAPIDS package cuml"
+    ).add_replacement((37, 55), "cuml>=24.04,<24.06,>=0.0.0a0")
+    alpha_spec.check_package_spec(
+        linter, args, loader.document_anchors[0], used_anchors, composed.value[2]
+    )
+    assert linter.warnings == expected_linter.warnings
+    assert used_anchors == {"cudf"}
+
+    expected_linter.add_warning(
+        (58, 75), "add alpha spec for RAPIDS package rmm"
+    ).add_replacement((58, 75), "rmm>=24.04,<24.06,>=0.0.0a0")
+    alpha_spec.check_package_spec(
+        linter, args, loader.document_anchors[0], used_anchors, composed.value[3]
+    )
+    assert linter.warnings == expected_linter.warnings
+    assert used_anchors == {"cudf"}
+
 
 @pytest.mark.parametrize(
     ["content", "indices"],