In times of crisis such as the current corona pandemic, the need for up-to-date statistical data for early assessment of the resulting economic impact is particularly high. The newly-developed experimental leading indicator for turnover development from monthly advance VAT returns helps to meet this data requirement. With a time-lag of less than 30 days, it allows for statements on the turnover development of the non-financial business economy. This contribution explains the special features of the data source and deals with important methodological aspects of the evaluation of the data and the provision of the leading indicator as a turnover index.