Two-tier or three-tier group, how to determine the group hierarchical structure, what are the principles?

This question is more professional, a good friend of mine in Huacai consulting work, some time ago is so said to me, about the group's two-tier and three-tier structure, not only is the management range and level of the problem, then what is the case, the two-tier is appropriate, what is the case, the three-tier is appropriate, please remember the following two principles, one, is the principle of competition in the marketplace, and accordingly to determine the two-tier or three-tier, and secondly, the risk control as the principle to determine the two-tier or three-tier. The second is the principle of risk control, according to which the decision of two or three levels should be made. In addition to the central enterprises, the State-owned Assets Supervision and Administration Commission (SASAC) has a clear provision that the group company shall not exceed three levels, but for the use of two or three levels of hierarchical structure, there is no which hard and fast rules.