HK import volume 2018: USD $627 billion [1]
HK export volume 2018: USD $568 billion [2]
The top 2 imports are: (see [3])
1. Electrical machinery, equipment: US$307.7 billion (53.2% of total imports)
2. Machinery including computers: US$66.4 billion (11.5%)
HK has only 7 million people. There's no way it can consume that much import nor produce that much export, especially not consuming $307 billion worth of machine equipment. Hong Kong is China's 2nd top trading partner [4]; China is basically using Hong Kong as a trading proxy to evade sanction. Most of the imports are purchased by China because it cannot buy them legally and has to use HK's "autonomous" status to import. Most of the exports are routed by China to take advantage of its tax free zone status.
Not to mention 70% of the foreign money going into China every year is via Hong Kong. Killing Hong Kong's "autonomous" status is the stupidest move done by China in the recent years. It allows the outside world to plug the last gateway into China.
[1] https://www.tid.gov.hk/english/aboutus/publications/tradesta...
[2] https://www.tid.gov.hk/english/aboutus/publications/tradesta...
[3] http://www.worldstopexports.com/hong-kongs-top-10-imports/
[4] http://www.worldstopexports.com/chinas-top-import-partners/