diff --git a/lib/ach/records/file_header.rb b/lib/ach/records/file_header.rb
index <HASH>..<HASH> 100644
--- a/lib/ach/records/file_header.rb
+++ b/lib/ach/records/file_header.rb
@@ -5,7 +5,7 @@ module ACH::Records
     const_field :record_type, '1'
     const_field :priority_code, '01'
     field :immediate_destination, String, lambda { |f| f.rjust(10) }, nil, /\A(\d{9,10}|)\z/
-    field :immediate_origin, String, lambda { |f| f.rjust(10) }, nil, /\A[A-Z\d\s]{1}?\d{9}\z/
+    field :immediate_origin, String, lambda { |f| f.rjust(10) }, nil, /\A[A-Z\d\s]{1}?\d{9}\s?\z/
     field :transmission_datetime, Time,
         lambda { |f| f.strftime('%y%m%d%H%M')},
         lambda { Time.now }
IMS-<I> allow appending space to immediate origin