diff --git a/piker/data/_source.py b/piker/data/_source.py
index 2f5f61ed..9afcb191 100644
--- a/piker/data/_source.py
+++ b/piker/data/_source.py
@@ -33,7 +33,7 @@ ohlc_fields = [
     ('high', float),
     ('low', float),
     ('close', float),
-    ('volume', int),
+    ('volume', float),
     ('bar_wap', float),
 ]