(10)Information on links of control between legal units is needed in order to define enterprise groups, delineate the enterprises correctly, profile large and complex units and study the level of concentration on particular markets. Enterprise group information improves the quality of the business registers and can be used to reduce the risk of disclosure of confidential data. Certain financial data are often more meaningful at the level of the group or subgroup than at that of the individual enterprise; indeed, they may be available only at the level of the group or subgroup. Recording enterprise group data makes possible, when necessary, surveys of the group rather than of the group's enterprises, and this may reduce the response burden significantly. In order to register enterprise groups, business registers should be further harmonised.