Because Chinese nationals who are residents of Hong Kong and Macau cannot automatically lose Chinese nationality under Article 9 even after acquiring foreign nationality (see above), such persons would only lose Chinese nationality if they renounce Chinese nationality (see above).
If a person concurrently holds de jure Chinese nationality and foreign nationality or citizenship, he or she will be treated solely as a Chinese national when the person is physically present on PRC soil (including Hong Kong and Macao), as per Article 3 and the Master Nationality Rule [REF].