diff --git a/ParProcCo/nxdata_aggregator.py b/ParProcCo/nxdata_aggregator.py
index aad2f3a..8f74035 100644
--- a/ParProcCo/nxdata_aggregator.py
+++ b/ParProcCo/nxdata_aggregator.py
@@ -73,7 +73,7 @@ def _initialise_arrays(self) -> None:
         self._get_all_axes()
 
         self.axes_mins = [np.inf] * self.data_dimensions
-        self.axes_maxs = [np.NINF] * self.data_dimensions
+        self.axes_maxs = [-np.inf] * self.data_dimensions
 
         for axis_set in self.all_axes:
             for j, axis in enumerate(axis_set):