diff --git a/pemi/pipes/pd.py b/pemi/pipes/pd.py
index b75fd0c..60456a1 100644
--- a/pemi/pipes/pd.py
+++ b/pemi/pipes/pd.py
@@ -175,13 +175,14 @@ def __init__(self, field, forks, **kwargs):
         )
 
     def flow(self):
-        grouped = self.sources['main'].df.groupby(self.field)
+        work_df = self.sources['main'].df.copy()
+        grouped = work_df.groupby(self.field)
 
         for fork in self.forks:
             if fork in grouped.groups:
                 self.targets[fork].df = grouped.get_group(fork).copy()
             else:
-                self.targets[fork].df = pd.DataFrame(columns=self.sources['main'].df.columns)
+                self.targets[fork].df = pd.DataFrame(columns=work_df.columns)
 
         remainder = set(grouped.groups.keys()) - set(self.forks)
         if len(remainder) > 0:
@@ -189,7 +190,13 @@ def flow(self):
                 [grouped.get_group(r) for r in remainder]
             ).sort_index()
         else:
-            self.targets['remainder'].df = pd.DataFrame(columns=self.sources['main'].df.columns)
+            self.targets['remainder'].df = pd.DataFrame(columns=work_df.columns)
+
+        if None in work_df[self.field].unique():
+            self.targets['remainder'].df = pd.concat(
+                [self.targets['remainder'].df, work_df[work_df[self.field].isna()]]
+            ).sort_index()
+
 
 class PdLambdaPipe(pemi.Pipe):
     '''
diff --git a/tests/pipes/test_pd.py b/tests/pipes/test_pd.py
index c59229f..bddd75b 100644
--- a/tests/pipes/test_pd.py
+++ b/tests/pipes/test_pd.py
@@ -549,8 +549,8 @@ def pipe(self):
         )
 
         df = pd.DataFrame({
-            'target': ['create', 'update', 'update', 'else1', 'create', 'else2'],
-            'values': [1, 2, 3, 4, 5, 6]
+            'target': ['create', 'update', 'update', 'else1', 'create', 'else2', '', None],
+            'values': [1, 2, 3, 4, 5, 6, 7, 8]
         })
 
         pipe.sources['main'].df = df
@@ -592,9 +592,9 @@ def test_it_forks_data_to_update(self, pipe):
 
     def test_it_puts_unknown_values_in_remainder(self, pipe):
         expected_df = pd.DataFrame({
-            'target': ['else1', 'else2'],
-            'values': [4, 6]
-        }, index=[3, 5])
+            'target': ['else1', 'else2', '', None],
+            'values': [4, 6, 7, 8]
+        }, index=[3, 5, 6, 7])
         actual_df = pipe.targets['remainder'].df
         pt.assert_frame_equal(actual_df, expected_df)