A manager of a small investment company has been successfully using index funds for limited market timing. Growth has allowed her to move into picking stocks. She is considering two small and highly variable listed stocks, but is concerned about the risk that these investments might add to her "portfolio." Provides a lead-in to the CAPM. Students learn about total risk, non-diversifiable or portfolio risk, and (CAPM) beta, and calculate variability of the stocks separately, and portfolio variance with and without the stocks, to see how an extremely risky (but low-beta) stock actually reduces risk; and calculate stock betas.