Black Mesa Corporation, US is that the one in New Mexico?

I don't know. Quick search show only references to some fictional organization from Half-Life computer game. That is why I accounted it as interesting.

Probably you have some official US business online catalogues where you could find registration data for US company by name. I just don't know where to look for such online services.

Also check another companies in "upstreams" tab, may be there will be more weird stuff I'm not aware about.

Black Mesa Corporation, US is that the one in New Mexico?

I don't know. Quick search show only references to some fictional organization from Half-Life computer game.

Probably you have some official US business online catalogues where you could find registration data for US company by name. I just don't know where to look for such online services.