diff --git a/zipline/gens/utils.py b/zipline/gens/utils.py
index 9bd8f2c5..32a57a4f 100644
--- a/zipline/gens/utils.py
+++ b/zipline/gens/utils.py
@@ -52,7 +52,6 @@ def assert_trade_protocol(event):
     assert_datasource_protocol(event)
 
     assert event.type == DATASOURCE_TYPE.TRADE
-    assert isinstance(event.sid, int)
     assert isinstance(event.price, numbers.Real)
     assert isinstance(event.volume, numbers.Integral)
     assert isinstance(event.dt, datetime)