“a set of brand assets and liabilities linked to a brand, its name and symbol, that add to or subtract from the value provided by a product or service to a firm and / or to that firm's customers”. For assets or liabilities to underlie brand equity they must be linked to the name and / or symbol of the brand. If the brand's name or symbol should change, some or all of the assets or liabilities could be affected and even lost, although some might be shifted to a new name and symbol. The assets and liabilities on which brand equity is based will differ from context to context. However, they can be usefully grouped into five categories: