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 Twitter Inc. common stock.
Rates of Return
Twitter Inc., monthly rates of return
| Twitter Inc. (TWTR) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceTWTR,t1 | DividendTWTR,t1 | RTWTR,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2017 | $17.62 | 2,278.87 | ||||
| 1. | Feb 28, 2017 | $15.77 | -10.50% | 2,363.64 | 3.72% | |
| 2. | Mar 31, 2017 | $14.95 | -5.20% | 2,362.72 | -0.04% | |
| 3. | Apr 30, 2017 | $16.48 | 10.23% | 2,384.20 | 0.91% | |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2021 | $43.94 | -17.93% | 4,567.00 | -0.83% | |
| 59. | Dec 31, 2021 | $43.22 | -1.64% | 4,766.18 | 4.36% | |
| Average (R): | 2.59% | 1.36% | ||||
| Standard deviation: | 14.93% | 4.48% | ||||
| Twitter Inc. (TWTR) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceTWTR,t1 | DividendTWTR,t1 | RTWTR,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2017 | $17.62 | 2,278.87 | ||||
| 1. | Feb 28, 2017 | $15.77 | -10.50% | 2,363.64 | 3.72% | |
| 2. | Mar 31, 2017 | $14.95 | -5.20% | 2,362.72 | -0.04% | |
| 3. | Apr 30, 2017 | $16.48 | 10.23% | 2,384.20 | 0.91% | |
| 4. | May 31, 2017 | $18.32 | 11.17% | 2,411.80 | 1.16% | |
| 5. | Jun 30, 2017 | $17.87 | -2.46% | 2,423.41 | 0.48% | |
| 6. | Jul 31, 2017 | $16.09 | -9.96% | 2,470.30 | 1.93% | |
| 7. | Aug 31, 2017 | $16.91 | 5.10% | 2,471.65 | 0.05% | |
| 8. | Sep 30, 2017 | $16.87 | -0.24% | 2,519.36 | 1.93% | |
| 9. | Oct 31, 2017 | $20.62 | 22.23% | 2,575.26 | 2.22% | |
| 10. | Nov 30, 2017 | $20.58 | -0.19% | 2,647.58 | 2.81% | |
| 11. | Dec 31, 2017 | $24.01 | 16.67% | 2,673.61 | 0.98% | |
| 12. | Jan 31, 2018 | $25.81 | 7.50% | 2,823.81 | 5.62% | |
| 13. | Feb 28, 2018 | $31.86 | 23.44% | 2,713.83 | -3.89% | |
| 14. | Mar 31, 2018 | $29.01 | -8.95% | 2,640.87 | -2.69% | |
| 15. | Apr 30, 2018 | $30.31 | 4.48% | 2,648.05 | 0.27% | |
| 16. | May 31, 2018 | $34.70 | 14.48% | 2,705.27 | 2.16% | |
| 17. | Jun 30, 2018 | $43.67 | 25.85% | 2,718.37 | 0.48% | |
| 18. | Jul 31, 2018 | $31.87 | -27.02% | 2,816.29 | 3.60% | |
| 19. | Aug 31, 2018 | $35.18 | 10.39% | 2,901.52 | 3.03% | |
| 20. | Sep 30, 2018 | $28.46 | -19.10% | 2,913.98 | 0.43% | |
| 21. | Oct 31, 2018 | $34.75 | 22.10% | 2,711.74 | -6.94% | |
| 22. | Nov 30, 2018 | $31.45 | -9.50% | 2,760.17 | 1.79% | |
| 23. | Dec 31, 2018 | $28.74 | -8.62% | 2,506.85 | -9.18% | |
| 24. | Jan 31, 2019 | $33.56 | 16.77% | 2,704.10 | 7.87% | |
| 25. | Feb 28, 2019 | $30.78 | -8.28% | 2,784.49 | 2.97% | |
| 26. | Mar 31, 2019 | $32.88 | 6.82% | 2,834.40 | 1.79% | |
| 27. | Apr 30, 2019 | $39.91 | 21.38% | 2,945.83 | 3.93% | |
| 28. | May 31, 2019 | $36.44 | -8.69% | 2,752.06 | -6.58% | |
| 29. | Jun 30, 2019 | $34.90 | -4.23% | 2,941.76 | 6.89% | |
| 30. | Jul 31, 2019 | $42.31 | 21.23% | 2,980.38 | 1.31% | |
| 31. | Aug 31, 2019 | $42.65 | 0.80% | 2,926.46 | -1.81% | |
| 32. | Sep 30, 2019 | $41.20 | -3.40% | 2,976.74 | 1.72% | |
| 33. | Oct 31, 2019 | $29.97 | -27.26% | 3,037.56 | 2.04% | |
| 34. | Nov 30, 2019 | $30.91 | 3.14% | 3,140.98 | 3.40% | |
| 35. | Dec 31, 2019 | $32.05 | 3.69% | 3,230.78 | 2.86% | |
| 36. | Jan 31, 2020 | $32.48 | 1.34% | 3,225.52 | -0.16% | |
| 37. | Feb 29, 2020 | $33.20 | 2.22% | 2,954.22 | -8.41% | |
| 38. | Mar 31, 2020 | $24.56 | -26.02% | 2,584.59 | -12.51% | |
| 39. | Apr 30, 2020 | $28.68 | 16.78% | 2,912.43 | 12.68% | |
| 40. | May 31, 2020 | $30.97 | 7.98% | 3,044.31 | 4.53% | |
| 41. | Jun 30, 2020 | $29.79 | -3.81% | 3,100.29 | 1.84% | |
| 42. | Jul 31, 2020 | $36.40 | 22.19% | 3,271.12 | 5.51% | |
| 43. | Aug 31, 2020 | $40.58 | 11.48% | 3,500.31 | 7.01% | |
| 44. | Sep 30, 2020 | $44.50 | 9.66% | 3,363.00 | -3.92% | |
| 45. | Oct 31, 2020 | $41.36 | -7.06% | 3,269.96 | -2.77% | |
| 46. | Nov 30, 2020 | $46.51 | 12.45% | 3,621.63 | 10.75% | |
| 47. | Dec 31, 2020 | $54.15 | 16.43% | 3,756.07 | 3.71% | |
| 48. | Jan 31, 2021 | $50.53 | -6.69% | 3,714.24 | -1.11% | |
| 49. | Feb 28, 2021 | $77.06 | 52.50% | 3,811.15 | 2.61% | |
| 50. | Mar 31, 2021 | $63.63 | -17.43% | 3,972.89 | 4.24% | |
| 51. | Apr 30, 2021 | $55.22 | -13.22% | 4,181.17 | 5.24% | |
| 52. | May 31, 2021 | $58.00 | 5.03% | 4,204.11 | 0.55% | |
| 53. | Jun 30, 2021 | $68.81 | 18.64% | 4,297.50 | 2.22% | |
| 54. | Jul 31, 2021 | $69.75 | 1.37% | 4,395.26 | 2.27% | |
| 55. | Aug 31, 2021 | $64.50 | -7.53% | 4,522.68 | 2.90% | |
| 56. | Sep 30, 2021 | $60.39 | -6.37% | 4,307.54 | -4.76% | |
| 57. | Oct 31, 2021 | $53.54 | -11.34% | 4,605.38 | 6.91% | |
| 58. | Nov 30, 2021 | $43.94 | -17.93% | 4,567.00 | -0.83% | |
| 59. | Dec 31, 2021 | $43.22 | -1.64% | 4,766.18 | 4.36% | |
| Average (R): | 2.59% | 1.36% | ||||
| Standard deviation: | 14.93% | 4.48% | ||||
Show all
1 Data in US$ per share of common stock, adjusted for splits and stock dividends.
2 Rate of return on common stock of TWTR during period t
3 Rate of return on S&P 500 (the market portfolio proxy) during period t
Variance and Covariance
Twitter Inc., calculation of variance and covariance of returns
| t | Date | RTWTR,t | RS&P 500,t | (RTWTR,t–RTWTR)2 | (RS&P 500,t–RS&P 500)2 | (RTWTR,t–RTWTR)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 28, 2017 | -10.50% | 3.72% | 171.38 | 5.58 | -30.92 |
| 2. | Mar 31, 2017 | -5.20% | -0.04% | 60.71 | 1.95 | 10.88 |
| 3. | Apr 30, 2017 | 10.23% | 0.91% | 58.41 | 0.20 | -3.43 |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2021 | -17.93% | -0.83% | 421.16 | 4.80 | 44.97 |
| 59. | Dec 31, 2021 | -1.64% | 4.36% | 17.90 | 9.02 | -12.71 |
| Total (Σ): | 12,929.79 | 1,164.17 | 806.82 | |||
| t | Date | RTWTR,t | RS&P 500,t | (RTWTR,t–RTWTR)2 | (RS&P 500,t–RS&P 500)2 | (RTWTR,t–RTWTR)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 28, 2017 | -10.50% | 3.72% | 171.38 | 5.58 | -30.92 |
| 2. | Mar 31, 2017 | -5.20% | -0.04% | 60.71 | 1.95 | 10.88 |
| 3. | Apr 30, 2017 | 10.23% | 0.91% | 58.41 | 0.20 | -3.43 |
| 4. | May 31, 2017 | 11.17% | 1.16% | 73.50 | 0.04 | -1.72 |
| 5. | Jun 30, 2017 | -2.46% | 0.48% | 25.48 | 0.77 | 4.42 |
| 6. | Jul 31, 2017 | -9.96% | 1.93% | 157.57 | 0.33 | -7.24 |
| 7. | Aug 31, 2017 | 5.10% | 0.05% | 6.27 | 1.70 | -3.26 |
| 8. | Sep 30, 2017 | -0.24% | 1.93% | 8.00 | 0.33 | -1.62 |
| 9. | Oct 31, 2017 | 22.23% | 2.22% | 385.61 | 0.74 | 16.91 |
| 10. | Nov 30, 2017 | -0.19% | 2.81% | 7.76 | 2.10 | -4.04 |
| 11. | Dec 31, 2017 | 16.67% | 0.98% | 198.10 | 0.14 | -5.27 |
| 12. | Jan 31, 2018 | 7.50% | 5.62% | 24.06 | 18.15 | 20.90 |
| 13. | Feb 28, 2018 | 23.44% | -3.89% | 434.67 | 27.59 | -109.51 |
| 14. | Mar 31, 2018 | -8.95% | -2.69% | 133.11 | 16.37 | 46.68 |
| 15. | Apr 30, 2018 | 4.48% | 0.27% | 3.57 | 1.18 | -2.05 |
| 16. | May 31, 2018 | 14.48% | 2.16% | 141.42 | 0.64 | 9.55 |
| 17. | Jun 30, 2018 | 25.85% | 0.48% | 540.95 | 0.76 | -20.32 |
| 18. | Jul 31, 2018 | -27.02% | 3.60% | 876.91 | 5.04 | -66.46 |
| 19. | Aug 31, 2018 | 10.39% | 3.03% | 60.75 | 2.78 | 13.00 |
| 20. | Sep 30, 2018 | -19.10% | 0.43% | 470.61 | 0.86 | 20.14 |
| 21. | Oct 31, 2018 | 22.10% | -6.94% | 380.62 | 68.86 | -161.89 |
| 22. | Nov 30, 2018 | -9.50% | 1.79% | 146.12 | 0.18 | -5.17 |
| 23. | Dec 31, 2018 | -8.62% | -9.18% | 125.63 | 111.00 | 118.09 |
| 24. | Jan 31, 2019 | 16.77% | 7.87% | 201.05 | 42.39 | 92.31 |
| 25. | Feb 28, 2019 | -8.28% | 2.97% | 118.28 | 2.61 | -17.56 |
| 26. | Mar 31, 2019 | 6.82% | 1.79% | 17.90 | 0.19 | 1.84 |
| 27. | Apr 30, 2019 | 21.38% | 3.93% | 353.03 | 6.62 | 48.35 |
| 28. | May 31, 2019 | -8.69% | -6.58% | 127.38 | 62.97 | 89.56 |
| 29. | Jun 30, 2019 | -4.23% | 6.89% | 46.48 | 30.64 | -37.74 |
| 30. | Jul 31, 2019 | 21.23% | 1.31% | 347.46 | 0.00 | -0.84 |
| 31. | Aug 31, 2019 | 0.80% | -1.81% | 3.20 | 10.03 | 5.66 |
| 32. | Sep 30, 2019 | -3.40% | 1.72% | 35.90 | 0.13 | -2.16 |
| 33. | Oct 31, 2019 | -27.26% | 2.04% | 890.97 | 0.47 | -20.45 |
| 34. | Nov 30, 2019 | 3.14% | 3.40% | 0.30 | 4.19 | 1.11 |
| 35. | Dec 31, 2019 | 3.69% | 2.86% | 1.20 | 2.25 | 1.65 |
| 36. | Jan 31, 2020 | 1.34% | -0.16% | 1.56 | 2.31 | 1.90 |
| 37. | Feb 29, 2020 | 2.22% | -8.41% | 0.14 | 95.43 | 3.66 |
| 38. | Mar 31, 2020 | -26.02% | -12.51% | 818.87 | 192.37 | 396.90 |
| 39. | Apr 30, 2020 | 16.78% | 12.68% | 201.17 | 128.29 | 160.65 |
| 40. | May 31, 2020 | 7.98% | 4.53% | 29.08 | 10.05 | 17.10 |
| 41. | Jun 30, 2020 | -3.81% | 1.84% | 40.98 | 0.23 | -3.08 |
| 42. | Jul 31, 2020 | 22.19% | 5.51% | 384.04 | 17.24 | 81.37 |
| 43. | Aug 31, 2020 | 11.48% | 7.01% | 79.06 | 31.91 | 50.23 |
| 44. | Sep 30, 2020 | 9.66% | -3.92% | 49.96 | 27.89 | -37.32 |
| 45. | Oct 31, 2020 | -7.06% | -2.77% | 93.08 | 17.01 | 39.79 |
| 46. | Nov 30, 2020 | 12.45% | 10.75% | 97.22 | 88.30 | 92.65 |
| 47. | Dec 31, 2020 | 16.43% | 3.71% | 191.40 | 5.54 | 32.57 |
| 48. | Jan 31, 2021 | -6.69% | -1.11% | 86.06 | 6.11 | 22.93 |
| 49. | Feb 28, 2021 | 52.50% | 2.61% | 2,491.18 | 1.57 | 62.45 |
| 50. | Mar 31, 2021 | -17.43% | 4.24% | 400.79 | 8.33 | -57.78 |
| 51. | Apr 30, 2021 | -13.22% | 5.24% | 249.92 | 15.09 | -61.41 |
| 52. | May 31, 2021 | 5.03% | 0.55% | 5.97 | 0.65 | -1.98 |
| 53. | Jun 30, 2021 | 18.64% | 2.22% | 257.48 | 0.75 | 13.86 |
| 54. | Jul 31, 2021 | 1.37% | 2.27% | 1.50 | 0.84 | -1.12 |
| 55. | Aug 31, 2021 | -7.53% | 2.90% | 102.39 | 2.38 | -15.59 |
| 56. | Sep 30, 2021 | -6.37% | -4.76% | 80.35 | 37.39 | 54.81 |
| 57. | Oct 31, 2021 | -11.34% | 6.91% | 194.18 | 30.87 | -77.43 |
| 58. | Nov 30, 2021 | -17.93% | -0.83% | 421.16 | 4.80 | 44.97 |
| 59. | Dec 31, 2021 | -1.64% | 4.36% | 17.90 | 9.02 | -12.71 |
| Total (Σ): | 12,929.79 | 1,164.17 | 806.82 | |||
Show all
VarianceTWTR = Σ(RTWTR,t–RTWTR)2 ÷ (59 – 1)
= 12,929.79 ÷ (59 – 1)
= 222.93
VarianceS&P 500 = Σ(RS&P 500,t–RS&P 500)2 ÷ (59 – 1)
= 1,164.17 ÷ (59 – 1)
= 20.07
CovarianceTWTR, S&P 500 = Σ(RTWTR,t–RTWTR)×(RS&P 500,t–RS&P 500) ÷ (59 – 1)
= 806.82 ÷ (59 – 1)
= 13.91
Systematic Risk (β) Estimation
| VarianceTWTR | 222.93 |
| VarianceS&P 500 | 20.07 |
| CovarianceTWTR, S&P 500 | 13.91 |
| Correlation coefficientTWTR, S&P 5001 | 0.21 |
| βTWTR2 | 0.69 |
| αTWTR3 | 1.65% |
Calculations
1 Correlation coefficientTWTR, S&P 500
= CovarianceTWTR, S&P 500 ÷ (Standard deviationTWTR × Standard deviationS&P 500)
= 13.91 ÷ (14.93% × 4.48%)
= 0.21
2 βTWTR
= CovarianceTWTR, S&P 500 ÷ VarianceS&P 500
= 13.91 ÷ 20.07
= 0.69
3 αTWTR
= AverageTWTR – βTWTR × AverageS&P 500
= 2.59% – 0.69 × 1.36%
= 1.65%
Expected Rate of Return
| Assumptions | ||
| Rate of return on LT Treasury Composite1 | RF | 4.83% |
| Expected rate of return on market portfolio2 | E(RM) | 14.44% |
| Systematic risk (β) of Twitter Inc. common stock | βTWTR | 0.69 |
| Expected rate of return on Twitter Inc. common stock3 | E(RTWTR) | 11.49% |
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(RTWTR) = RF + βTWTR [E(RM) – RF]
= 4.83% + 0.69 [14.44% – 4.83%]
= 11.49%