I guess AT&T is a good classic example. This article should be a good starting point for details: https://en.wikipedia.org/wiki/Breakup_of_the_Bell_System https

I guess AT&T is a good classic example. This article should be a good starting point for details: https://en.wikipedia.org/wiki/Breakup_of_the_Bell_System https://en.wikipedia.org/wiki/Breakup_of_the_Bell_System