I'm surprised nobody has mentioned East Lake yet. It is basically all corporate memberships, except for those that had ones before it was purchased in 1993 as I understand it. No one company, but definitely a corporate course.
Armco Steel used to own at least two courses in Ohio and Western PA but they have been sold over the years. Another one of our member courses (Beaver Lakes) was once owned by J&L Steel but sold to the members years ago.
This used to be much more prevalent that it is today I think.