diff --git a/beancount_import/source/generic_importer_source.py b/beancount_import/source/generic_importer_source.py
index a2df6c2..0cdf646 100644
--- a/beancount_import/source/generic_importer_source.py
+++ b/beancount_import/source/generic_importer_source.py
@@ -35,8 +35,8 @@
 class ImporterSource(DescriptionBasedSource):
     def __init__(self,
                  directory: str,
-                 account: str,
                  importer: ImporterProtocol,
+                 account: Optional[str]=None, # use None for importers that are not authoritative and would not clear any postings
                  **kwargs) -> None:
         super().__init__(**kwargs)
         self.directory = os.path.expanduser(directory)
@@ -57,11 +57,16 @@ def name(self) -> str:
         return self.importer.name()
 
     def prepare(self, journal: 'JournalEditor', results: SourceResults) -> None:
-        results.add_account(self.account)
+        if self.account:
+            results.add_account(self.account)
 
         entries = OrderedDict() #type: Dict[Hashable, List[Directive]]
         for f in self.files:
             f_entries = self.importer.extract(f, existing_entries=journal.entries)
+            # if the importer is not authoritative, add all entries to pending
+            if not self.account:
+                results.add_pending_entries(map(self._make_import_result, f_entries))
+                continue
             # collect  all entries in current statement, grouped by hash
             hashed_entries = OrderedDict() #type: Dict[Hashable, Directive]
             for entry in f_entries:
@@ -77,14 +82,15 @@ def prepare(self, journal: 'JournalEditor', results: SourceResults) -> None:
                     n = len(entries[key_])
                 entries.setdefault(key_, []).extend(hashed_entries[key_][n:])
 
-        get_pending_and_invalid_entries(
-            raw_entries=list(itertools.chain.from_iterable(entries.values())),
-            journal_entries=journal.all_entries,
-            account_set=set([self.account]),
-            get_key_from_posting=_get_key_from_posting,
-            get_key_from_raw_entry=self._get_key_from_imported_entry,
-            make_import_result=self._make_import_result,
-            results=results)
+        if self.account:
+            get_pending_and_invalid_entries(
+                raw_entries=list(itertools.chain.from_iterable(entries.values())),
+                journal_entries=journal.all_entries,
+                account_set=set([self.account]),
+                get_key_from_posting=_get_key_from_posting,
+                get_key_from_raw_entry=self._get_key_from_imported_entry,
+                make_import_result=self._make_import_result,
+                results=results)
 
     def _add_description(self, entry: Transaction):
         if not isinstance(entry, Transaction): return None