15 - File Form 5500 if Extension was filed. – 4/30 Plan Year

15- Return excess contributions for failed ADP/ACP test to avoid penalties – 11/30 Plan Year

28/29- File Form 1096 (transmittal form for Form 1099-R information copies) – All Plan Years

28/29 - File Form 5500 with schedules and audited financial statements, if applicable – 7/31 Plan Year