The issue is accessing said sources are difficult as the Vietnamese Government kinda sucks at digitizing and presenting financial and economic data.

Also, most of these subsidiaries are not publicly listed, so any revenue attached to them will be listed within the division it is a part of (Eg. Lotte Cultureworks VN revenue will be treated as part of the larger Lotte Cultureworks SEA bucket in any listings)

My hunch is they probably provide good data to Korean and Japanese financial data aggregators (eg. Mitsui or Shinhan), but I can't be bothered to brush up my Japanese, Korean, or Vietnamese on a Sunday for a random comment on a forum.

This is effort that companies pay people to do. I ain't doing it for free on my weekend