I've always wondered why companies would choose to have their advertisement triggered whenever their company's name was searched for. For example, if a searcher users the search query "Nike", why would Nike pay for the advertisement when obviously, they already rank #1 organically. I can imagine their CPC would be fairly low (anyone have a guess as to what that might be?). I can also imagine that there's a marketing tactic to having "Nike" fill up half the page. However, is it really worth the money?? Would love to hear your inputs please. Thank you.
Mostly it's done to ensure that nobody else is getting that top spot for your brand name. In most cases other people can bid on your brand name, as long as they don't imply in the ad that they are 'you', in my results in the UK I can see a well-known sportswear chain also showing ads for 'nike' - if the company wasn't advertising they would be in the top spot ahead of nike. Also, as you say, you dominate the page for that search term, and it is going to be the cheapest click you can get - a quick comparison on the google keyword tool on brand names I've bid on suggests that the cpc is about 4 times less than the tool suggests for a brand if you are the brand itself.