Research projects on Business Groups are mainly based on a novel database of Italian firms belonging to groups. Specifically, in order to provide an updated map of the presence and the role of the groups in Italy, it is necessary to have data at firm level. To this end, we have built a database of Italian business groups considering the different sectors of economic activity as described by the Ateco 2007 codes. The database was developed using information on the ownership of companies provided by AIDA. Using this information it was possible to develop the map of business groups in 2015. From the AIDA database, the balance sheet data of the Italian firms belonging to and not to the group for the years 2008-2015 have been extracted. We also included foreign firms belonging to groups in the final database. Of foreign firms, the Aida database only provides information on ownership (ownership and control) but not the financial and economic data. For this reason of each group, we have available the complete information of the Italian affiliated firms while about the foreign ones only the information on ownership and control. Moreover, we have excluded from the final dataset those companies that in the Aida database under the heading "type of firm/company" are defined as "families or group of people" rather than "companies" (they were cases in which the company was a standalone or family company). Although we did not consider family companies, we preserved those groups with their head represented by a family company. Therefore, in the final dataset there will be groups where the parent company no longer appears ("head") but there are only its controlled firms. The total of groups to which it is not possible to associate a "head" because represented by a "family or groups of people" is 18,653.
This new database on groups also gives the possibility to know if a firm belongs simultaneously to a group and an industrial district, useful information to know the presence or absence of so-called "district groups".
To identify the industrial districts, we used information on the local labor systems (SLL) defined by ISTAT using the flows of daily journeys home / work - the so-called commuting - measured during the census of the population. ISTAT identified 611 SLL in 2011. Among these, it identified 141 industrial districts.
The dataset includes about 110 thousand groups with about 190 thousand affiliated companies (joint-stock companies).