diff --git a/setup.py b/setup.py
index adc5c79f..3567ac03 100644
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,7 @@ else:
 
 setup(
     name='zipline',
-    version='0.5.10',
+    version='0.5.11.dev',
     description='A backtester for financial algorithms.',
     author='Quantopian Inc.',
     author_email='opensource@quantopian.com',
diff --git a/zipline/__init__.py b/zipline/__init__.py
index 56db419c..4fe138a8 100644
--- a/zipline/__init__.py
+++ b/zipline/__init__.py
@@ -5,6 +5,7 @@ Zipline
 # This is *not* a place to dump arbitrary classes/modules for convenience,
 # it is a place to expose the public interfaces.
 
+__version__ = 0.5.11.dev
 
 from . import data
 from . import finance