For an investor, venture capitalists and a manager of a growth firm it s always of interest to know which impact the market risk has on the stock of the firm. The more exposed the firm is to market risk intuitively, the higher is the firms beta. My belief is that the bottom up beta approach gives a truer reflection and a more updated beta value than a CAPM regression beta on the firm s current business mix, the CAPM beta takes only the past stock prices into consideration.