1. It is illegal to exchange Hong Kong dollars privately to earn the difference. According to the provisions of the criminal law, if the circumstances are serious, they shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall also be fined not less than one time but not more than five times the illegal income.

2. Article 2 of the Interpretation on Several Issues Concerning the Application of Laws in Handling Criminal Cases of Illegal Payment of Settlement Funds and Illegal Trading of Foreign Exchange stipulates that illegal foreign exchange transactions such as buying and selling foreign exchange in disguised form are conducted in violation of state regulations, disrupting the order of the financial market. If the circumstances are serious, he shall be convicted and punished for the crime of illegal business operation in accordance with the provisions of Item 4 of Article 225 of the Criminal Law.