Not widely known to the general search engine marketers (SEM), there is a procedure that search engines will honor which is brand and trademark protection. It varies from Google, to Bing but the fundamentals are quite similar.
In this instance, the search engine will provide brand and trademark owners protection for their brand that they own and restrict other advertisers from bidding on those terms. One is able to ring fence a brand/trademark to ensure that competitors, or affiliates are not bidding on your brand.
Lastly, it helps with cost management for your paid search program as this will mean that there is less competition, or you can have the option of not promoting your brand if your SEO program ranks well in on the SERP page.