diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index 847d69597c..fcd4491fd3 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -36,7 +36,7 @@ def author_to_author_sort(author):
         return author
     author = _bracket_pat.sub('', author).strip()
     tokens = author.split()
-    if tokens[-1] not in ('Inc.', 'Inc'):
+    if tokens and tokens[-1] not in ('Inc.', 'Inc'):
         tokens = tokens[-1:] + tokens[:-1]
         if len(tokens) > 1 and method != 'nocomma':
             tokens[0] += ','