Capital Asset Pricing Model (CAPM)
Capital asset pricing model (CAPM) indicates what should be the expected or required rate of return on risky assets like Comcast Corp. common stock.
Rates of Return
Comcast Corp., monthly rates of return
| Comcast Corp. (CMCSA) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceCMCSA,t1 | DividendCMCSA,t1 | RCMCSA,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2020 | $43.19 | 3,225.52 | ||||
| 1. | Feb 29, 2020 | $40.43 | -6.39% | 2,954.22 | -8.41% | |
| 2. | Mar 31, 2020 | $34.38 | $0.23 | -14.40% | 2,584.59 | -12.51% |
| 3. | Apr 30, 2020 | $37.63 | 9.45% | 2,912.43 | 12.68% | |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2024 | $43.19 | -1.10% | 6,032.38 | 5.73% | |
| 59. | Dec 31, 2024 | $37.53 | -13.10% | 5,881.63 | -2.50% | |
| Average (R): | 0.27% | 1.16% | ||||
| Standard deviation: | 7.81% | 5.28% | ||||
| Comcast Corp. (CMCSA) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceCMCSA,t1 | DividendCMCSA,t1 | RCMCSA,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2020 | $43.19 | 3,225.52 | ||||
| 1. | Feb 29, 2020 | $40.43 | -6.39% | 2,954.22 | -8.41% | |
| 2. | Mar 31, 2020 | $34.38 | $0.23 | -14.40% | 2,584.59 | -12.51% |
| 3. | Apr 30, 2020 | $37.63 | 9.45% | 2,912.43 | 12.68% | |
| 4. | May 31, 2020 | $39.60 | 5.24% | 3,044.31 | 4.53% | |
| 5. | Jun 30, 2020 | $38.98 | $0.23 | -0.98% | 3,100.29 | 1.84% |
| 6. | Jul 31, 2020 | $42.80 | 9.80% | 3,271.12 | 5.51% | |
| 7. | Aug 31, 2020 | $44.81 | 4.70% | 3,500.31 | 7.01% | |
| 8. | Sep 30, 2020 | $46.26 | 3.24% | 3,363.00 | -3.92% | |
| 9. | Oct 31, 2020 | $42.24 | $0.23 | -8.19% | 3,269.96 | -2.77% |
| 10. | Nov 30, 2020 | $50.24 | 18.94% | 3,621.63 | 10.75% | |
| 11. | Dec 31, 2020 | $52.40 | 4.30% | 3,756.07 | 3.71% | |
| 12. | Jan 31, 2021 | $49.57 | $0.23 | -4.96% | 3,714.24 | -1.11% |
| 13. | Feb 28, 2021 | $52.72 | 6.35% | 3,811.15 | 2.61% | |
| 14. | Mar 31, 2021 | $54.11 | 2.64% | 3,972.89 | 4.24% | |
| 15. | Apr 30, 2021 | $56.15 | $0.25 | 4.23% | 4,181.17 | 5.24% |
| 16. | May 31, 2021 | $57.34 | 2.12% | 4,204.11 | 0.55% | |
| 17. | Jun 30, 2021 | $57.02 | -0.56% | 4,297.50 | 2.22% | |
| 18. | Jul 31, 2021 | $58.83 | $0.25 | 3.61% | 4,395.26 | 2.27% |
| 19. | Aug 31, 2021 | $60.68 | 3.14% | 4,522.68 | 2.90% | |
| 20. | Sep 30, 2021 | $55.93 | -7.83% | 4,307.54 | -4.76% | |
| 21. | Oct 31, 2021 | $51.43 | $0.25 | -7.60% | 4,605.38 | 6.91% |
| 22. | Nov 30, 2021 | $49.98 | -2.82% | 4,567.00 | -0.83% | |
| 23. | Dec 31, 2021 | $50.33 | 0.70% | 4,766.18 | 4.36% | |
| 24. | Jan 31, 2022 | $49.99 | $0.25 | -0.18% | 4,515.55 | -5.26% |
| 25. | Feb 28, 2022 | $46.76 | -6.46% | 4,373.94 | -3.14% | |
| 26. | Mar 31, 2022 | $46.82 | 0.13% | 4,530.41 | 3.58% | |
| 27. | Apr 30, 2022 | $39.76 | $0.27 | -14.50% | 4,131.93 | -8.80% |
| 28. | May 31, 2022 | $44.28 | 11.37% | 4,132.15 | 0.01% | |
| 29. | Jun 30, 2022 | $39.24 | -11.38% | 3,785.38 | -8.39% | |
| 30. | Jul 31, 2022 | $37.52 | $0.27 | -3.70% | 4,130.29 | 9.11% |
| 31. | Aug 31, 2022 | $36.19 | -3.54% | 3,955.00 | -4.24% | |
| 32. | Sep 30, 2022 | $29.33 | -18.96% | 3,585.62 | -9.34% | |
| 33. | Oct 31, 2022 | $31.74 | $0.27 | 9.14% | 3,871.98 | 7.99% |
| 34. | Nov 30, 2022 | $36.64 | 15.44% | 4,080.11 | 5.38% | |
| 35. | Dec 31, 2022 | $34.97 | -4.56% | 3,839.50 | -5.90% | |
| 36. | Jan 31, 2023 | $39.35 | $0.27 | 13.30% | 4,076.60 | 6.18% |
| 37. | Feb 28, 2023 | $37.17 | -5.54% | 3,970.15 | -2.61% | |
| 38. | Mar 31, 2023 | $37.91 | 1.99% | 4,109.31 | 3.51% | |
| 39. | Apr 30, 2023 | $41.37 | $0.29 | 9.89% | 4,169.48 | 1.46% |
| 40. | May 31, 2023 | $39.35 | -4.88% | 4,179.83 | 0.25% | |
| 41. | Jun 30, 2023 | $41.55 | 5.59% | 4,376.86 | 4.71% | |
| 42. | Jul 31, 2023 | $45.26 | $0.29 | 9.63% | 4,588.96 | 4.85% |
| 43. | Aug 31, 2023 | $46.76 | 3.31% | 4,507.66 | -1.77% | |
| 44. | Sep 30, 2023 | $44.34 | -5.18% | 4,288.05 | -4.87% | |
| 45. | Oct 31, 2023 | $41.29 | $0.29 | -6.22% | 4,193.80 | -2.20% |
| 46. | Nov 30, 2023 | $41.89 | 1.45% | 4,567.80 | 8.92% | |
| 47. | Dec 31, 2023 | $43.85 | 4.68% | 4,769.83 | 4.42% | |
| 48. | Jan 31, 2024 | $46.54 | $0.29 | 6.80% | 4,845.65 | 1.59% |
| 49. | Feb 29, 2024 | $42.85 | -7.93% | 5,096.27 | 5.17% | |
| 50. | Mar 31, 2024 | $43.35 | 1.17% | 5,254.35 | 3.10% | |
| 51. | Apr 30, 2024 | $38.11 | $0.29 | -11.42% | 5,035.69 | -4.16% |
| 52. | May 31, 2024 | $40.03 | 5.04% | 5,277.51 | 4.80% | |
| 53. | Jun 30, 2024 | $39.16 | -2.17% | 5,460.48 | 3.47% | |
| 54. | Jul 31, 2024 | $41.27 | $0.31 | 6.18% | 5,522.30 | 1.13% |
| 55. | Aug 31, 2024 | $39.57 | -4.12% | 5,648.40 | 2.28% | |
| 56. | Sep 30, 2024 | $41.77 | 5.56% | 5,762.48 | 2.02% | |
| 57. | Oct 31, 2024 | $43.67 | $0.31 | 5.29% | 5,705.45 | -0.99% |
| 58. | Nov 30, 2024 | $43.19 | -1.10% | 6,032.38 | 5.73% | |
| 59. | Dec 31, 2024 | $37.53 | -13.10% | 5,881.63 | -2.50% | |
| Average (R): | 0.27% | 1.16% | ||||
| Standard deviation: | 7.81% | 5.28% | ||||
Show all
1 Data in US$ per share of common stock, adjusted for splits and stock dividends.
2 Rate of return on common stock of CMCSA during period t
3 Rate of return on S&P 500 (the market portfolio proxy) during period t
Variance and Covariance
Comcast Corp., calculation of variance and covariance of returns
| t | Date | RCMCSA,t | RS&P 500,t | (RCMCSA,t–RCMCSA)2 | (RS&P 500,t–RS&P 500)2 | (RCMCSA,t–RCMCSA)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 29, 2020 | -6.39% | -8.41% | 44.32 | 91.63 | 63.72 |
| 2. | Mar 31, 2020 | -14.40% | -12.51% | 214.97 | 186.96 | 200.48 |
| 3. | Apr 30, 2020 | 9.45% | 12.68% | 84.39 | 132.78 | 105.86 |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2024 | -1.10% | 5.73% | 1.87 | 20.87 | -6.24 |
| 59. | Dec 31, 2024 | -13.10% | -2.50% | 178.80 | 13.40 | 48.94 |
| Total (Σ): | 3,534.09 | 1,618.62 | 1,646.94 | |||
| t | Date | RCMCSA,t | RS&P 500,t | (RCMCSA,t–RCMCSA)2 | (RS&P 500,t–RS&P 500)2 | (RCMCSA,t–RCMCSA)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 29, 2020 | -6.39% | -8.41% | 44.32 | 91.63 | 63.72 |
| 2. | Mar 31, 2020 | -14.40% | -12.51% | 214.97 | 186.96 | 200.48 |
| 3. | Apr 30, 2020 | 9.45% | 12.68% | 84.39 | 132.78 | 105.86 |
| 4. | May 31, 2020 | 5.24% | 4.53% | 24.69 | 11.34 | 16.73 |
| 5. | Jun 30, 2020 | -0.98% | 1.84% | 1.57 | 0.46 | -0.85 |
| 6. | Jul 31, 2020 | 9.80% | 5.51% | 90.88 | 18.91 | 41.46 |
| 7. | Aug 31, 2020 | 4.70% | 7.01% | 19.62 | 34.17 | 25.89 |
| 8. | Sep 30, 2020 | 3.24% | -3.92% | 8.82 | 25.85 | -15.10 |
| 9. | Oct 31, 2020 | -8.19% | -2.77% | 71.56 | 15.43 | 33.23 |
| 10. | Nov 30, 2020 | 18.94% | 10.75% | 348.67 | 92.03 | 179.13 |
| 11. | Dec 31, 2020 | 4.30% | 3.71% | 16.26 | 6.51 | 10.29 |
| 12. | Jan 31, 2021 | -4.96% | -1.11% | 27.34 | 5.18 | 11.89 |
| 13. | Feb 28, 2021 | 6.35% | 2.61% | 37.06 | 2.10 | 8.81 |
| 14. | Mar 31, 2021 | 2.64% | 4.24% | 5.62 | 9.50 | 7.31 |
| 15. | Apr 30, 2021 | 4.23% | 5.24% | 15.72 | 16.66 | 16.18 |
| 16. | May 31, 2021 | 2.12% | 0.55% | 3.43 | 0.38 | -1.13 |
| 17. | Jun 30, 2021 | -0.56% | 2.22% | 0.68 | 1.12 | -0.87 |
| 18. | Jul 31, 2021 | 3.61% | 2.27% | 11.20 | 1.24 | 3.73 |
| 19. | Aug 31, 2021 | 3.14% | 2.90% | 8.28 | 3.02 | 5.00 |
| 20. | Sep 30, 2021 | -7.83% | -4.76% | 65.52 | 35.02 | 47.91 |
| 21. | Oct 31, 2021 | -7.60% | 6.91% | 61.87 | 33.10 | -45.25 |
| 22. | Nov 30, 2021 | -2.82% | -0.83% | 9.52 | 3.98 | 6.16 |
| 23. | Dec 31, 2021 | 0.70% | 4.36% | 0.19 | 10.24 | 1.39 |
| 24. | Jan 31, 2022 | -0.18% | -5.26% | 0.20 | 41.21 | 2.86 |
| 25. | Feb 28, 2022 | -6.46% | -3.14% | 45.27 | 18.47 | 28.91 |
| 26. | Mar 31, 2022 | 0.13% | 3.58% | 0.02 | 5.84 | -0.33 |
| 27. | Apr 30, 2022 | -14.50% | -8.80% | 218.12 | 99.14 | 147.05 |
| 28. | May 31, 2022 | 11.37% | 0.01% | 123.24 | 1.34 | -12.83 |
| 29. | Jun 30, 2022 | -11.38% | -8.39% | 135.69 | 91.26 | 111.28 |
| 30. | Jul 31, 2022 | -3.70% | 9.11% | 15.70 | 63.21 | -31.50 |
| 31. | Aug 31, 2022 | -3.54% | -4.24% | 14.53 | 29.22 | 20.60 |
| 32. | Sep 30, 2022 | -18.96% | -9.34% | 369.49 | 110.27 | 201.85 |
| 33. | Oct 31, 2022 | 9.14% | 7.99% | 78.69 | 46.58 | 60.54 |
| 34. | Nov 30, 2022 | 15.44% | 5.38% | 230.17 | 17.76 | 63.93 |
| 35. | Dec 31, 2022 | -4.56% | -5.90% | 23.28 | 49.82 | 34.05 |
| 36. | Jan 31, 2023 | 13.30% | 6.18% | 169.79 | 25.14 | 65.33 |
| 37. | Feb 28, 2023 | -5.54% | -2.61% | 33.72 | 14.23 | 21.91 |
| 38. | Mar 31, 2023 | 1.99% | 3.51% | 2.97 | 5.49 | 4.04 |
| 39. | Apr 30, 2023 | 9.89% | 1.46% | 92.64 | 0.09 | 2.92 |
| 40. | May 31, 2023 | -4.88% | 0.25% | 26.52 | 0.83 | 4.70 |
| 41. | Jun 30, 2023 | 5.59% | 4.71% | 28.35 | 12.62 | 18.91 |
| 42. | Jul 31, 2023 | 9.63% | 4.85% | 87.62 | 13.58 | 34.49 |
| 43. | Aug 31, 2023 | 3.31% | -1.77% | 9.29 | 8.60 | -8.94 |
| 44. | Sep 30, 2023 | -5.18% | -4.87% | 29.62 | 36.40 | 32.83 |
| 45. | Oct 31, 2023 | -6.22% | -2.20% | 42.14 | 11.28 | 21.81 |
| 46. | Nov 30, 2023 | 1.45% | 8.92% | 1.41 | 60.17 | 9.20 |
| 47. | Dec 31, 2023 | 4.68% | 4.42% | 19.47 | 10.64 | 14.39 |
| 48. | Jan 31, 2024 | 6.80% | 1.59% | 42.63 | 0.18 | 2.80 |
| 49. | Feb 29, 2024 | -7.93% | 5.17% | 67.16 | 16.09 | -32.87 |
| 50. | Mar 31, 2024 | 1.17% | 3.10% | 0.81 | 3.77 | 1.75 |
| 51. | Apr 30, 2024 | -11.42% | -4.16% | 136.55 | 28.33 | 62.20 |
| 52. | May 31, 2024 | 5.04% | 4.80% | 22.77 | 13.26 | 17.37 |
| 53. | Jun 30, 2024 | -2.17% | 3.47% | 5.95 | 5.32 | -5.63 |
| 54. | Jul 31, 2024 | 6.18% | 1.13% | 34.97 | 0.00 | -0.17 |
| 55. | Aug 31, 2024 | -4.12% | 2.28% | 19.24 | 1.26 | -4.92 |
| 56. | Sep 30, 2024 | 5.56% | 2.02% | 28.02 | 0.74 | 4.54 |
| 57. | Oct 31, 2024 | 5.29% | -0.99% | 25.24 | 4.63 | -10.81 |
| 58. | Nov 30, 2024 | -1.10% | 5.73% | 1.87 | 20.87 | -6.24 |
| 59. | Dec 31, 2024 | -13.10% | -2.50% | 178.80 | 13.40 | 48.94 |
| Total (Σ): | 3,534.09 | 1,618.62 | 1,646.94 | |||
Show all
VarianceCMCSA = Σ(RCMCSA,t–RCMCSA)2 ÷ (59 – 1)
= 3,534.09 ÷ (59 – 1)
= 60.93
VarianceS&P 500 = Σ(RS&P 500,t–RS&P 500)2 ÷ (59 – 1)
= 1,618.62 ÷ (59 – 1)
= 27.91
CovarianceCMCSA, S&P 500 = Σ(RCMCSA,t–RCMCSA)×(RS&P 500,t–RS&P 500) ÷ (59 – 1)
= 1,646.94 ÷ (59 – 1)
= 28.40
Systematic Risk (β) Estimation
| VarianceCMCSA | 60.93 |
| VarianceS&P 500 | 27.91 |
| CovarianceCMCSA, S&P 500 | 28.40 |
| Correlation coefficientCMCSA, S&P 5001 | 0.69 |
| βCMCSA2 | 1.02 |
| αCMCSA3 | -0.91% |
Calculations
1 Correlation coefficientCMCSA, S&P 500
= CovarianceCMCSA, S&P 500 ÷ (Standard deviationCMCSA × Standard deviationS&P 500)
= 28.40 ÷ (7.81% × 5.28%)
= 0.69
2 βCMCSA
= CovarianceCMCSA, S&P 500 ÷ VarianceS&P 500
= 28.40 ÷ 27.91
= 1.02
3 αCMCSA
= AverageCMCSA – βCMCSA × AverageS&P 500
= 0.27% – 1.02 × 1.16%
= -0.91%
Expected Rate of Return
| Assumptions | ||
| Rate of return on LT Treasury Composite1 | RF | 4.78% |
| Expected rate of return on market portfolio2 | E(RM) | 14.43% |
| Systematic risk (β) of Comcast Corp. common stock | βCMCSA | 1.02 |
| Expected rate of return on Comcast Corp. common stock3 | E(RCMCSA) | 14.59% |
1 Unweighted average of bid yields on all outstanding fixed-coupon U.S. Treasury bonds neither due or callable in less than 10 years (risk-free rate of return proxy).
3 E(RCMCSA) = RF + βCMCSA [E(RM) – RF]
= 4.78% + 1.02 [14.43% – 4.78%]
= 14.59%