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7.2·7 min read

CAPM & the Cost of Equity

The cost of equity is the risk-free rate plus beta times the market risk premium. Riskier stock, higher demanded return.

By the end you can
  • Apply the CAPM formula
  • Identify where each input comes from
  • Compute a cost of equity end to end

Equity investors don't quote you a rate the way lenders do, so we infer their required return with the Capital Asset Pricing Model (CAPM). The idea: investors demand the plus a premium for bearing the stock's market risk.

Re=Rf+β(RmRf)R_e = R_f + \beta\,(R_m - R_f)
R_f = risk-free rate; β = how much the stock moves with the market; (R_m - R_f) = market risk premium.
InputWhere it comes from
R_f ()Yield on the 10-year US Treasury
R_m - R_f ()Expected market return over risk-free; typically 5–8%
β ()Stock's sensitivity to the market; from Bloomberg or comps
Worked example · Cost of equity for Max's Bikes
Given
  • R_f: 2%
  • β: 1.3
  • Market return R_m: 9%
Solution
  1. 1.Plug into
    Re=0.02+1.3(0.090.02)R_e = 0.02 + 1.3\,(0.09 - 0.02)
  2. 2.Compute
    =0.02+1.3×0.07=0.02+0.091=0.111= 0.02 + 1.3 \times 0.07 = 0.02 + 0.091 = 0.111
Answer

= 11.1%. The is 7%; a of 1.3 scales it to 9.1%, on top of the 2% risk-free base.

Check yourself

Risk-free rate 3%, beta 0.8, market risk premium 6%. What is the cost of equity?

Try it: cost of equity (CAPM)

Risk-free rate plus beta times the market risk premium.

Risk-free rate (Rf)3.0%
Beta1.20
Market risk premium6.0%
Cost of equity
10.2%
3.0% + 1.20 x 6.0%