diff --git a/nomad/datamodel/dft.py b/nomad/datamodel/dft.py
index 8125c893505e6b8ad5fc7798a86ec3fb2a86181b..ba96edb7895f39cd10b7e7209971c3428f509c3e 100644
--- a/nomad/datamodel/dft.py
+++ b/nomad/datamodel/dft.py
@@ -156,7 +156,9 @@ class DFTMetadata(MSection):
     xc_functional = Quantity(
         type=str, default='not processed',
         description='The libXC based xc functional classification used in the simulation.',
-        a_search=Search(statistic_values=list(xc_treatments.values()) + ['unavailable', 'not processed']))
+        a_search=Search(
+            statistic_values=list(xc_treatments.values()) + ['unavailable', 'not processed'],
+            statistic_size=100))
 
     system = Quantity(
         type=str, default='not processed',