(2) The subject matter is a big concept of civil law (also called the object of legal relationship). What does it mean here? Refers to the company, refers to the equity, refers to the right to use state-owned land. According to the WTO and relevant arrangements between the two sides of the strait, Hong Kong companies can enjoy national treatment, including company, equity, land use rights and so on.
(3) If mainland companies must be used to purchase the equity of Hong Kong companies, the mainland should collect taxes and fees, because mainland companies have made equity transactions, paid the cost and obtained valuable equity. As the buyer, it shall pay the business tax, deed tax and income tax (20%) that generate the premium. If the declared amount is inconsistent with the land value involved in the equity, the tax bureau has the right to assess the tax recovery by itself.
Yes, not paying taxes is a crime, so I won't go into details here;
(4) Easy to clinch a deal (beneficial to the seller), and it is unwise for the mainland to pay more taxes. If it is for listing, the current mainland real estate IPO will not be accepted. Of course, HKEx does not accept the listing of domestic real estate assets as RITS, and the listing of mainland real estate in Hong Kong requires the approval of the Ministry of Commerce in accordance with the procedures for approving foreign investment, which is very difficult and basically impossible. So your goal is hard to achieve.
Another risk is that there are regulations in the Mainland that the land shall not be developed within two years from the beginning (subject to the planning permission), and the current situation of the project needs due diligence.