diff --git a/betfairutil/__init__.py b/betfairutil/__init__.py
index 5b1c3d4..311e82c 100644
--- a/betfairutil/__init__.py
+++ b/betfairutil/__init__.py
@@ -2745,7 +2745,11 @@ def g():
         return df
 
 
-def publish_time_to_datetime(publish_time: int) -> datetime.datetime:
+def publish_time_to_datetime(
+    publish_time: Optional[int],
+) -> Optional[datetime.datetime]:
+    if publish_time is None:
+        return
     return datetime.datetime.utcfromtimestamp(publish_time / 1000).replace(
         tzinfo=datetime.timezone.utc
     )
diff --git a/tests/test_non_prices.py b/tests/test_non_prices.py
index 292f5d6..76b17ff 100644
--- a/tests/test_non_prices.py
+++ b/tests/test_non_prices.py
@@ -1301,3 +1301,7 @@ def test_get_total_volume_traded_from_prices_file(
         f.write("\n")
     total_volume_traded = get_total_volume_traded_from_prices_file(path_to_prices_file)
     assert total_volume_traded is None
+
+
+def test_publish_time_to_datetime():
+    assert publish_time_to_datetime(None) is None