A firm that has under-positioned a product has failed to communicate a clear positioning to the end-consumer. This means that the product positioning is vague or that the firm has tried to communicate too much about the product (and the consumers are confused about what the product stands for). In either case, the positioning is quite weak and we have not effectively communicated any real points-of-difference.
Almost the opposite of that problem, is referred to as over-positioning. This is where we have over emphasized one or two points of the product and the target market now has been very narrow perception of what the product offers. So rather than communicating array of both points-of-parity and points-of-difference, the firm has focused on one point-of-difference only. The problem here is that the target market may interpret the product as being a very specialized solution, which would dramatically limit its overall market appeal and sales potential.