diff --git a/src/pyhf/tensor/numpy_backend.py b/src/pyhf/tensor/numpy_backend.py
index 1118d4b1de..b1bdcf7880 100644
--- a/src/pyhf/tensor/numpy_backend.py
+++ b/src/pyhf/tensor/numpy_backend.py
@@ -9,6 +9,8 @@
 # Needed while numpy lower bound is older than v1.21.0
 if TYPE_CHECKING:
     from numpy.typing import ArrayLike, DTypeLike, NBitBase, NDArray
+else:
+    NBitBase = "NBitBase"
 
 from scipy import special
 from scipy.special import gammaln, xlogy
@@ -16,7 +18,7 @@
 
 from pyhf.typing import Literal, Shape
 
-T = TypeVar("T", bound="NBitBase")
+T = TypeVar("T", bound=NBitBase)
 
 Tensor = Union["NDArray[np.number[T]]", "NDArray[np.bool_]"]
 FloatIntOrBool = Literal["float", "int", "bool"]