Businesses and self-employed operators buying construction services must file monthly reports to the Tax Administration by October 6. Companies must give details on their contracts if the value goes over the 15,000-euro threshold. All customers must give details on the contracts they have bought.

In addition, details on the employees must be submitted for all construction sites where there are more than one companies being active, if the aggregate value of the contracts made with the site customer goes over the 15,000-euro threshold. The main implementer i.e. project supervisor of the construction site is responsible for the reporting. Companies can submit their information electronically either in the suomi.fi service using a fillable web form or via the Ilmoitin.fi service using a file transfer or a software interface.