You cannot copyright a name. I assume you mean trademark; and even then unless the ad network has rules against it there is nothing in law that specifically for

You cannot copyright a name. I assume you mean trademark; and even then unless the ad network has rules against it there is nothing in law that specifically forbids using a competitor's name in this way. Trademark is mostly concerned with "pretending to be someone you're not." So if you pretend to be Nike and sell fake shoes, then it is a powerful set of laws, but if someone writes a critical review of a Nike's tennis shoes then they cannot demand it be pulled down. As I said Google/Bing might have specific rules against this kind of thing but you really don't have the law on your side. They're allowed to be critical of you as long as they don't misrepresent themselves as being you.