By means of an amended basic model of financial markets, I reformulate the classical CAPM in two fundamental respects. The first is to have the B-pricing basis extended to include two more market factors; the second is to have the pricing model allow for the hedging relation between ambiguity and ambiguity aversion in the general case of market incompleteness. As a result, the reformulated CAPM captures not only systematic information associated with market factors but also systemic information associated with the state of market structure. Moreover, it becomes relatively more informational efficient than the classical CAPM is.