The attribution of companies to a common group would need to be based on legal control, that is, ownership of some defined threshold of equity – 51% or higher. But a much lower share of equity often is sufficient to secure de facto control, thus encouraging groups to adapt their capital structure – moving firms in and out of the group’s boundaries – to minimize tax liabilities.
其次，在集团公司统一核算方面并没有共同的法规；的确，在许多欧盟国家的商法中都没有对集团公司的法律定义。多家公司和同一个集团的归属关系需要以合法的控制为基础，即要有某种明确的股份门槛—51%及以上。但通常通过低得多的股份也能获得实际上的控制权，因此这就鼓励了各集团调整其资本结构—将公司在集团的边界内外挪移—从而使税收义务最小化。