diff --git a/zipline/assets/asset_writer.py b/zipline/assets/asset_writer.py
index d3484432..4d2690af 100644
--- a/zipline/assets/asset_writer.py
+++ b/zipline/assets/asset_writer.py
@@ -289,7 +289,7 @@ class AssetDBWriter(with_metaclass(ABCMeta)):
             'symbol': None,
             'asset_name': None,
             'start_date': 0,
-            'end_date': 2 ** 63 - 1,
+            'end_date': 2 ** 62 - 1,
             'first_traded': None,
             'exchange': None,
             'fuzzy': None,
@@ -332,7 +332,7 @@ class AssetDBWriter(with_metaclass(ABCMeta)):
             'root_symbol': None,
             'asset_name': None,
             'start_date': 0,
-            'end_date': 2 ** 63 - 1,
+            'end_date': 2 ** 62 - 1,
             'first_traded': None,
             'exchange': None,
             'notice_date': None,