diff --git a/zipline/finance/performance.py b/zipline/finance/performance.py
index c4b0a112..cc149f97 100644
--- a/zipline/finance/performance.py
+++ b/zipline/finance/performance.py
@@ -384,7 +384,7 @@ class PerformanceTracker(object):
         self.day_count += 1.0
         # move the market day markers forward
         if self.market_close < trading.environment.last_trading_day:
-            _, self.market_close = \
+            self.market_open, self.market_close = \
                 trading.environment.next_open_and_close(self.market_open)
         else:
             self.market_close = self.sim_params.last_close