For a long time, Chinese companies have been buying controlling / major interest in European companies and then sucking out the IP, etc. back to China, and often fully killing the European entity. [1]
It's very common for a core technology to just be a firm with a few hundred people doing a very specific thing, which is useful in itself, but also has access to big portions of the specs/designs/IP of which it's being integrated into.
Think: Advanced aircraft engines, ASML's EUV machines, weapon systems, etc.
The same actually happens in reverse too with aggressively one-sided joint "partnerships" like when China essentially played the world's high speed rail manufacturers against each other to steal their IP. [2]
[1] https://www.npr.org/2018/10/03/639636532/chinese-companies-g...
[2] http://www.ipbrief.net/2011/08/07/digestion-and-re-innovatio...