From my experience the value of the brand is all about what additional benefit (in the form of profit most the time time), having the brand gives, compared to not having the brand. I have found the best way of doing this is to determine what cash flows one can generate as a result of the existing business and brand, compared to what i would be able to generate if i was using my own no name brand. In most instances the difference although difficult to strip out, will give a good indication. I am in the Groceries sector, we bought a store, it performed moderately for 4 years, we changed its brand name to a well known one we own, and overnight the store performed well. Was quite an amazing case study.