diff --git a/jass/models/inittable.py b/jass/models/inittable.py
index 7a4d2ced0f5d8db694e0e866dc8a87b828e8c769..6fbdd8c3b194df6977da81beaea4420988f5a809 100644
--- a/jass/models/inittable.py
+++ b/jass/models/inittable.py
@@ -265,7 +265,7 @@ def create_inittable_file(
     which_cols.extend(list(pheno_select))
     hdf_init.put("PhenoList", pheno_list, format="table", data_columns=True)
     hdf_init.put("Regions", regions, format="table", data_columns=True)
-    sum_stat_tab_min_itemsizes = {"snp_ids": 80, "Ref_allele": 70, "Alt_allele": 70}
+    sum_stat_tab_min_itemsizes = {"snp_ids": 310, "Ref_allele": 300, "Alt_allele": 300}
 
     regions_bychr = regions.groupby("chr")
 
diff --git a/jass/models/worktable.py b/jass/models/worktable.py
index a67697a0df434f7ccdf098af1db98c9424395dc0..ee48567c4008a030e4ed5abb5232363ddfd43e54 100644
--- a/jass/models/worktable.py
+++ b/jass/models/worktable.py
@@ -430,20 +430,20 @@ def create_worktable_file(
 
     regions = read_hdf(init_file_path, "Regions").index.tolist()
     sum_stat_tab_min_itemsizes = {
-        "snp_ids": 80,
+        "snp_ids": 310,
         "Region": 10,
         "CHR": 5,
-        "Ref_allele": 70,
-        "Alt_allele": 70,
+        "Ref_allele": 300,
+        "Alt_allele": 300,
     }
     region_sub_table_min_itemsizes = {
         "Region": 10,
         "index": 10,
         "CHR": 5,
-        "snp_ids": 80,
+        "snp_ids": 310,
         "signif_status": 20,
-        "Ref_allele": 70,
-        "Alt_allele": 70,
+        "Ref_allele": 300,
+        "Alt_allele": 300,
     }
 
     smart_na_computation = not (remove_nan)