Each company must define a clear process of period creation. This should be done, since creating a period at the wrong Point in the cycle (too late or too eary) or providing unclear assignment can have a fatal effect on the VAT Compliance process. It can be pointed out at the beginning of the Project that e.g. an accurate topical Picture of a VAT group can be ensured through the continuing period creating. When master data from the preperiod is to be adopted, a contemporary creation of periods is advisable especially regarding the case that tax codes are edited. Otherwise tax codes have to e changed manually later on. In short: which user creates which period and when.