SFU Beedie courses only. See the course list →
Business TutorBusiness Tutor
← Everything for Investments
Investments

Which risk earns a return?

Build the market portfolio, compare the CML with the SML, and use beta to judge returns and prices. Solve has 10 questions worked step by step.

Model and market · Step 1 of 12

Shared forecasts lead to one risky portfolio

  • Compare expected return and standard deviation over one period.
  • Use the same forecasts for every asset.
  • Borrow and lend at the same risk-free rate.
  • Pay no taxes or trading costs.
  • Take prices as given: one investor cannot move them.
HoldingShare of wealth
Common market basket60.00%
T-bills40.00%
Everyone uses the same risky basket; the share held may differ
The capital asset pricing model, or CAPM, connects the market's risk with the return investors require. Under its assumptions everyone chooses the same risky basket; risk aversion changes the amount held, not the basket's contents. Our invented examples last one year, with an effective annual risk-free rate of 3% and market SD of 20%.
Try it: Select an assumption to focus on it, then change the amount held in the common risky basket.
Assumption to examine
Share of wealth in the market60%
Market share
60.00%
Expected return
7.92%
Mix SD
12.00%
Market share y = (60 ÷ 100) = 0.6000.
T-bill share = (1 − 0.6000) = 0.4000.
E[RC] = Rf + y(E[RM] − Rf).
(0.03 + 0.6000 × (0.1120 − 0.03)) = 7.92%.
Check yourself
Two CAPM investors have different risk aversion but the same forecasts. What differs?
Key

E[R] means expected return; σ is standard deviation; σ² is variance. Rf is the effective annual risk-free rate, M is the market portfolio, y is the share of wealth held in M, β is beta and α is forecast return minus required return.

The CML uses total SD and applies to efficient T-bill–market mixes. The SML uses beta and prices every asset or portfolio. For how the optimal risky basket is found, see the tool “Diversification and efficient portfolios”.

Exam coming up and the CML and the SML keep swapping places?

Bring your problem sets. We work through them together until every type feels routine.

FAQ

Questions, answered.

Still unsure about something? Message us and you will hear back within a day.

See all questions
  • In person, we meet at the SFU Burnaby campus or in a private meeting room near Brentwood in Burnaby. Online sessions run on Zoom. You choose when you book.