The main uses of trademarks / company names / brand names in Paid Search PPC includes:

1. Using the trademark in the ad text (generally prohibited unless is permitted by the trademark owner or under some circumstances a reseller or publisher).

This is not approved if the trademark is on a recognised list held by Google, but this is not always the case, so it requires policing. Exceptions may be requested.

2. Using the trademark as keywords within the Ad Group to trigger the ad.

There have been many examples where advertisers have attempted to “hijack” brand traffic. You should check for infringements, e.g. through keyword ranking or reputation management software. You will need to ask Google to prevent this and continue to check.

This is straightforward to block if the trademark or brand name is a single term, but it is less straightforward if the trademark consists of several words, e.g. “Barclays bank”, “American Airlines” and the advertiser is broad matching on the non-trademark term, i.e. bank or airlines in this example. Decisions on these issues have been taken to the court and findings tend to vary, generally broad-matching is permitted under US legal judgements, but is less likely to be permitted under European law.

Further details are available from these Google blog posts, but the trademark law is evolving: - AdWords trademark advice 1

• AdWords trademark advice
• Adwords trademark summary

You can see that the situation differs between the US and elsewhere

The best place to follow recent judgement in the US are Eric Goldmans blog and in the UK, Europe: Outlaw PPC trademarks page