Besides the normal posting periods, SAP allows for defining a maximum four more posting periods, which are known as Special Periods as these are used for year-end closing activities. This is achieved by dividing the last posting period into more than one (maximum four) period. However, all the postings in these special periods should fall within the last posting period.
The special periods cannot be determined automatically by the system based on the posting date of the document. The special period needs to be manually entered into the 'posting period' field in the document header.