(WIKI: Semantic HTML is the use of HTML markup to reinforce the semantics, or meaning, of the information in webpages rather than merely to define its presentation or look. Semantic HTML is processed by regular web browsers as well as by many other user agents. CSS is used to suggest its presentation to human users.)
The straight answer to this is yes! But only if you are big enough. Some of the worlds biggest brand names and simply ignoring semantic markup because at the end of the day why would big name brands like Cole, Virgin and Tescos add organization markup to their page? Simply but they wouldn’t.
Only the business themselves will know if it is something to think about as with all aspects of SEO. After all if people know your brand name like the back of their hand why would you want to suggests anything but that brand?