diff --git a/skbase/testing/utils/deep_equals.py b/skbase/testing/utils/deep_equals.py
index 22370fde..c225fb38 100644
--- a/skbase/testing/utils/deep_equals.py
+++ b/skbase/testing/utils/deep_equals.py
@@ -15,6 +15,11 @@
 __all__: List[str] = ["deep_equals"]
 
 
+# flag variables for available soft dependencies
+pandas_available = _check_soft_dependencies("pandas", severity="none")
+numpy_available = _check_soft_dependencies("numpy", severity="none")
+
+
 def deep_equals(x, y, return_msg=False):
     """Test two objects for equality in value.
 
@@ -70,10 +75,6 @@ def ret(is_equal, msg):
     # we now know all types are the same
     # so now we compare values
 
-    # flag variables for available soft dependencies
-    pandas_available = _check_soft_dependencies("pandas", severity="none")
-    numpy_available = _check_soft_dependencies("numpy", severity="none")
-
     if numpy_available:
         import numpy as np
 
@@ -93,6 +94,8 @@ def ret(is_equal, msg):
         return ret(*_tuple_equals(x, y, return_msg=True))
     elif isinstance(x, dict):
         return ret(*_dict_equals(x, y, return_msg=True))
+    elif _is_npnan(x):
+        return ret(_is_npnan(y), f"type(x)={type(x)} != type(y)={type(y)}")
     elif isclass(x):
         return ret(x == y, f".class, x={x.__name__} != y={y.__name__}")
     elif type(x).__name__ == "ForecastingHorizon":
@@ -125,6 +128,17 @@ def _is_npndarray(x):
     return clstr == "ndarray"
 
 
+def _is_npnan(x):
+
+    if numpy_available:
+        import numpy as np
+
+        return isinstance(x, float) and np.isnan(x)
+
+    else:
+        return False
+
+
 def _coerce_list(x):
     """Coerce x to list."""
     if not isinstance(x, (list, tuple)):
diff --git a/skbase/testing/utils/tests/test_deep_equals.py b/skbase/testing/utils/tests/test_deep_equals.py
index 684c5b6f..a832e05a 100644
--- a/skbase/testing/utils/tests/test_deep_equals.py
+++ b/skbase/testing/utils/tests/test_deep_equals.py
@@ -16,6 +16,9 @@
     [([([([()])])])],
     np.array([2, 3, 4]),
     np.array([2, 4, 5]),
+    3.5,
+    4.2,
+    np.nan,
 ]
 
 
diff --git a/skbase/tests/conftest.py b/skbase/tests/conftest.py
index 7bb22766..b84ce692 100644
--- a/skbase/tests/conftest.py
+++ b/skbase/tests/conftest.py
@@ -122,6 +122,7 @@
             "_pandas_equals",
             "_dict_equals",
             "_is_pandas",
+            "_is_npnan",
             "_tuple_equals",
             "_fh_equals",
             "deep_equals",
@@ -152,6 +153,7 @@ class Parent(BaseObject):
     _tags = {"A": "1", "B": 2, "C": 1234, "3": "D"}
 
     def __init__(self, a="something", b=7, c=None):
+        """Initialize the class."""
         self.a = a
         self.b = b
         self.c = c