diff --git a/tests/pipeline/test_us_equity_pricing_loader.py b/tests/pipeline/test_us_equity_pricing_loader.py
index a10ea0fb..b75f4799 100644
--- a/tests/pipeline/test_us_equity_pricing_loader.py
+++ b/tests/pipeline/test_us_equity_pricing_loader.py
@@ -175,43 +175,43 @@ DIVIDENDS = DataFrame(
     [
         # Before query range, should be excluded.
         {'declared_date': Timestamp('2015-05-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-02', tz='UTC').to_datetime64(),
          'record_date': Timestamp('2015-06-03', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-05', tz='UTC').to_datetime64(),
          'amount': 90.0,
          'sid': 1},
         # First day of query range, should be excluded.
         {'declared_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-10', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-11', tz='UTC').to_datetime64(),
          'record_date': Timestamp('2015-06-15', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-17', tz='UTC').to_datetime64(),
          'amount': 80.0,
          'sid': 3},
         # Third day of query range, should have last_row of 2
         {'declared_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-12', tz='UTC').to_datetime64(),
-         'record_date': Timestamp('2015-06-15', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-15', tz='UTC').to_datetime64(),
+         'record_date': Timestamp('2015-06-16', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-17', tz='UTC').to_datetime64(),
          'amount': 70.0,
          'sid': 3},
         # After query range, should be excluded.
         {'declared_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-25', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-26', tz='UTC').to_datetime64(),
          'record_date': Timestamp('2015-06-28', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-30', tz='UTC').to_datetime64(),
          'amount': 60.0,
          'sid': 6},
         # Another action in query range, should have last_row of 3
         {'declared_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-15', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-16', tz='UTC').to_datetime64(),
          'record_date': Timestamp('2015-06-18', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-20', tz='UTC').to_datetime64(),
          'amount': 50.0,
          'sid': 3},
         # Last day of range.  Should have last_row of 7
         {'declared_date': Timestamp('2015-06-01', tz='UTC').to_datetime64(),
-         'ex_date': Timestamp('2015-06-19', tz='UTC').to_datetime64(),
-         'record_date': Timestamp('2015-06-22', tz='UTC').to_datetime64(),
+         'ex_date': Timestamp('2015-06-22', tz='UTC').to_datetime64(),
+         'record_date': Timestamp('2015-06-23', tz='UTC').to_datetime64(),
          'pay_date': Timestamp('2015-06-30', tz='UTC').to_datetime64(),
          'amount': 40.0,
          'sid': 3},
diff --git a/zipline/data/us_equity_pricing.py b/zipline/data/us_equity_pricing.py
index 59ab952b..12ec6a4b 100644
--- a/zipline/data/us_equity_pricing.py
+++ b/zipline/data/us_equity_pricing.py
@@ -27,6 +27,7 @@ from bcolz import (
 from click import progressbar
 from numpy import (
     array,
+    int64,
     float64,
     floating,
     full,
@@ -40,6 +41,7 @@ from pandas import (
     DataFrame,
     DatetimeIndex,
     read_csv,
+    to_datetime,
     Timestamp,
 )
 from six import (
@@ -647,6 +649,8 @@ class SQLiteAdjustmentWriter(object):
 
         calendar = self._calendar
 
+        effective_dates = full(len(amounts), -1, dtype=int64)
+
         for i, amount in enumerate(amounts):
             sid = sids[i]
             ex_date = ex_dates[i]
@@ -655,8 +659,11 @@ class SQLiteAdjustmentWriter(object):
             try:
                 prev_close = daily_bar_reader.spot_price(
                     sid, div_adj_date, 'close')
-                ratio = 1.0 - amount / (prev_close)
-                ratios[i] = ratio
+                if prev_close != 0.0:
+                    ratio = 1.0 - amount / prev_close
+                    ratios[i] = ratio
+                    # only assign effective_date when data is found
+                    effective_dates[i] = div_adj_date.value
             except NoDataOnDate:
                 logger.warn("Couldn't compute ratio for dividend %s" % {
                     'sid': sid,
@@ -665,7 +672,14 @@ class SQLiteAdjustmentWriter(object):
                 })
                 continue
 
-        effective_dates = ex_dates.astype('datetime64[s]').astype(uint32)
+        # Create a mask to filter out indices in the effective_date, sid, and
+        # ratio vectors for which a ratio was not calculable.
+        effective_mask = effective_dates != -1
+        effective_dates = effective_dates[effective_mask]
+        effective_dates = effective_dates.astype('datetime64[ns]').\
+            astype('datetime64[s]').astype(uint32)
+        sids = sids[effective_mask]
+        ratios = ratios[effective_mask]
 
         return DataFrame({
             'sid': sids,