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 Intuitive Surgical Inc. common stock.
Rates of Return
Intuitive Surgical Inc., monthly rates of return
| Intuitive Surgical Inc. (ISRG) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceISRG,t1 | DividendISRG,t1 | RISRG,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2019 | $174.55 | 2,704.10 | ||||
| 1. | Feb 28, 2019 | $182.54 | 4.58% | 2,784.49 | 2.97% | |
| 2. | Mar 31, 2019 | $190.19 | 4.19% | 2,834.40 | 1.79% | |
| 3. | Apr 30, 2019 | $170.21 | -10.51% | 2,945.83 | 3.93% | |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2023 | $310.84 | 18.54% | 4,567.80 | 8.92% | |
| 59. | Dec 31, 2023 | $337.36 | 8.53% | 4,769.83 | 4.42% | |
| Average (R): | 1.63% | 1.11% | ||||
| Standard deviation: | 10.24% | 5.31% | ||||
| Intuitive Surgical Inc. (ISRG) | Standard & Poor’s 500 (S&P 500) | |||||
|---|---|---|---|---|---|---|
| t | Date | PriceISRG,t1 | DividendISRG,t1 | RISRG,t2 | PriceS&P 500,t | RS&P 500,t3 |
| Jan 31, 2019 | $174.55 | 2,704.10 | ||||
| 1. | Feb 28, 2019 | $182.54 | 4.58% | 2,784.49 | 2.97% | |
| 2. | Mar 31, 2019 | $190.19 | 4.19% | 2,834.40 | 1.79% | |
| 3. | Apr 30, 2019 | $170.21 | -10.51% | 2,945.83 | 3.93% | |
| 4. | May 31, 2019 | $154.95 | -8.97% | 2,752.06 | -6.58% | |
| 5. | Jun 30, 2019 | $174.85 | 12.84% | 2,941.76 | 6.89% | |
| 6. | Jul 31, 2019 | $173.17 | -0.96% | 2,980.38 | 1.31% | |
| 7. | Aug 31, 2019 | $170.45 | -1.57% | 2,926.46 | -1.81% | |
| 8. | Sep 30, 2019 | $179.98 | 5.59% | 2,976.74 | 1.72% | |
| 9. | Oct 31, 2019 | $184.32 | 2.41% | 3,037.56 | 2.04% | |
| 10. | Nov 30, 2019 | $197.63 | 7.22% | 3,140.98 | 3.40% | |
| 11. | Dec 31, 2019 | $197.05 | -0.29% | 3,230.78 | 2.86% | |
| 12. | Jan 31, 2020 | $186.59 | -5.31% | 3,225.52 | -0.16% | |
| 13. | Feb 29, 2020 | $177.99 | -4.61% | 2,954.22 | -8.41% | |
| 14. | Mar 31, 2020 | $165.07 | -7.26% | 2,584.59 | -12.51% | |
| 15. | Apr 30, 2020 | $170.29 | 3.16% | 2,912.43 | 12.68% | |
| 16. | May 31, 2020 | $193.34 | 13.54% | 3,044.31 | 4.53% | |
| 17. | Jun 30, 2020 | $189.94 | -1.76% | 3,100.29 | 1.84% | |
| 18. | Jul 31, 2020 | $228.48 | 20.29% | 3,271.12 | 5.51% | |
| 19. | Aug 31, 2020 | $243.61 | 6.62% | 3,500.31 | 7.01% | |
| 20. | Sep 30, 2020 | $236.51 | -2.91% | 3,363.00 | -3.92% | |
| 21. | Oct 31, 2020 | $222.36 | -5.98% | 3,269.96 | -2.77% | |
| 22. | Nov 30, 2020 | $242.02 | 8.84% | 3,621.63 | 10.75% | |
| 23. | Dec 31, 2020 | $272.70 | 12.68% | 3,756.07 | 3.71% | |
| 24. | Jan 31, 2021 | $249.21 | -8.61% | 3,714.24 | -1.11% | |
| 25. | Feb 28, 2021 | $245.60 | -1.45% | 3,811.15 | 2.61% | |
| 26. | Mar 31, 2021 | $246.31 | 0.29% | 3,972.89 | 4.24% | |
| 27. | Apr 30, 2021 | $288.33 | 17.06% | 4,181.17 | 5.24% | |
| 28. | May 31, 2021 | $280.73 | -2.64% | 4,204.11 | 0.55% | |
| 29. | Jun 30, 2021 | $306.55 | 9.20% | 4,297.50 | 2.22% | |
| 30. | Jul 31, 2021 | $330.49 | 7.81% | 4,395.26 | 2.27% | |
| 31. | Aug 31, 2021 | $351.19 | 6.26% | 4,522.68 | 2.90% | |
| 32. | Sep 30, 2021 | $331.38 | -5.64% | 4,307.54 | -4.76% | |
| 33. | Oct 31, 2021 | $361.13 | 8.98% | 4,605.38 | 6.91% | |
| 34. | Nov 30, 2021 | $324.34 | -10.19% | 4,567.00 | -0.83% | |
| 35. | Dec 31, 2021 | $359.30 | 10.78% | 4,766.18 | 4.36% | |
| 36. | Jan 31, 2022 | $284.18 | -20.91% | 4,515.55 | -5.26% | |
| 37. | Feb 28, 2022 | $290.33 | 2.16% | 4,373.94 | -3.14% | |
| 38. | Mar 31, 2022 | $301.68 | 3.91% | 4,530.41 | 3.58% | |
| 39. | Apr 30, 2022 | $239.30 | -20.68% | 4,131.93 | -8.80% | |
| 40. | May 31, 2022 | $227.64 | -4.87% | 4,132.15 | 0.01% | |
| 41. | Jun 30, 2022 | $200.71 | -11.83% | 3,785.38 | -8.39% | |
| 42. | Jul 31, 2022 | $230.17 | 14.68% | 4,130.29 | 9.11% | |
| 43. | Aug 31, 2022 | $205.74 | -10.61% | 3,955.00 | -4.24% | |
| 44. | Sep 30, 2022 | $187.44 | -8.89% | 3,585.62 | -9.34% | |
| 45. | Oct 31, 2022 | $246.47 | 31.49% | 3,871.98 | 7.99% | |
| 46. | Nov 30, 2022 | $270.39 | 9.71% | 4,080.11 | 5.38% | |
| 47. | Dec 31, 2022 | $265.35 | -1.86% | 3,839.50 | -5.90% | |
| 48. | Jan 31, 2023 | $245.69 | -7.41% | 4,076.60 | 6.18% | |
| 49. | Feb 28, 2023 | $229.39 | -6.63% | 3,970.15 | -2.61% | |
| 50. | Mar 31, 2023 | $255.47 | 11.37% | 4,109.31 | 3.51% | |
| 51. | Apr 30, 2023 | $301.22 | 17.91% | 4,169.48 | 1.46% | |
| 52. | May 31, 2023 | $307.84 | 2.20% | 4,179.83 | 0.25% | |
| 53. | Jun 30, 2023 | $341.94 | 11.08% | 4,376.86 | 4.71% | |
| 54. | Jul 31, 2023 | $324.40 | -5.13% | 4,588.96 | 4.85% | |
| 55. | Aug 31, 2023 | $312.68 | -3.61% | 4,507.66 | -1.77% | |
| 56. | Sep 30, 2023 | $292.29 | -6.52% | 4,288.05 | -4.87% | |
| 57. | Oct 31, 2023 | $262.22 | -10.29% | 4,193.80 | -2.20% | |
| 58. | Nov 30, 2023 | $310.84 | 18.54% | 4,567.80 | 8.92% | |
| 59. | Dec 31, 2023 | $337.36 | 8.53% | 4,769.83 | 4.42% | |
| Average (R): | 1.63% | 1.11% | ||||
| Standard deviation: | 10.24% | 5.31% | ||||
Show all
1 Data in US$ per share of common stock, adjusted for splits and stock dividends.
2 Rate of return on common stock of ISRG during period t
3 Rate of return on S&P 500 (the market portfolio proxy) during period t
Variance and Covariance
Intuitive Surgical Inc., calculation of variance and covariance of returns
| t | Date | RISRG,t | RS&P 500,t | (RISRG,t–RISRG)2 | (RS&P 500,t–RS&P 500)2 | (RISRG,t–RISRG)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 28, 2019 | 4.58% | 2.97% | 8.70 | 3.49 | 5.51 |
| 2. | Mar 31, 2019 | 4.19% | 1.79% | 6.57 | 0.47 | 1.76 |
| 3. | Apr 30, 2019 | -10.51% | 3.93% | 147.20 | 7.98 | -34.28 |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| . | . | . | . | . | . | . |
| 58. | Nov 30, 2023 | 18.54% | 8.92% | 286.10 | 61.03 | 132.14 |
| 59. | Dec 31, 2023 | 8.53% | 4.42% | 47.67 | 11.00 | 22.90 |
| Total (Σ): | 6,085.09 | 1,634.30 | 2,217.97 | |||
| t | Date | RISRG,t | RS&P 500,t | (RISRG,t–RISRG)2 | (RS&P 500,t–RS&P 500)2 | (RISRG,t–RISRG)×(RS&P 500,t–RS&P 500) |
|---|---|---|---|---|---|---|
| 1. | Feb 28, 2019 | 4.58% | 2.97% | 8.70 | 3.49 | 5.51 |
| 2. | Mar 31, 2019 | 4.19% | 1.79% | 6.57 | 0.47 | 1.76 |
| 3. | Apr 30, 2019 | -10.51% | 3.93% | 147.20 | 7.98 | -34.28 |
| 4. | May 31, 2019 | -8.97% | -6.58% | 112.20 | 59.04 | 81.39 |
| 5. | Jun 30, 2019 | 12.84% | 6.89% | 125.79 | 33.49 | 64.91 |
| 6. | Jul 31, 2019 | -0.96% | 1.31% | 6.70 | 0.04 | -0.54 |
| 7. | Aug 31, 2019 | -1.57% | -1.81% | 10.23 | 8.50 | 9.32 |
| 8. | Sep 30, 2019 | 5.59% | 1.72% | 15.71 | 0.37 | 2.43 |
| 9. | Oct 31, 2019 | 2.41% | 2.04% | 0.61 | 0.88 | 0.74 |
| 10. | Nov 30, 2019 | 7.22% | 3.40% | 31.29 | 5.28 | 12.86 |
| 11. | Dec 31, 2019 | -0.29% | 2.86% | 3.69 | 3.07 | -3.37 |
| 12. | Jan 31, 2020 | -5.31% | -0.16% | 48.10 | 1.61 | 8.80 |
| 13. | Feb 29, 2020 | -4.61% | -8.41% | 38.89 | 90.57 | 59.35 |
| 14. | Mar 31, 2020 | -7.26% | -12.51% | 78.96 | 185.44 | 121.01 |
| 15. | Apr 30, 2020 | 3.16% | 12.68% | 2.36 | 134.06 | 17.77 |
| 16. | May 31, 2020 | 13.54% | 4.53% | 141.81 | 11.71 | 40.75 |
| 17. | Jun 30, 2020 | -1.76% | 1.84% | 11.46 | 0.54 | -2.48 |
| 18. | Jul 31, 2020 | 20.29% | 5.51% | 348.32 | 19.40 | 82.20 |
| 19. | Aug 31, 2020 | 6.62% | 7.01% | 24.95 | 34.82 | 29.47 |
| 20. | Sep 30, 2020 | -2.91% | -3.92% | 20.63 | 25.29 | 22.84 |
| 21. | Oct 31, 2020 | -5.98% | -2.77% | 57.91 | 15.00 | 29.47 |
| 22. | Nov 30, 2020 | 8.84% | 10.75% | 52.05 | 93.10 | 69.61 |
| 23. | Dec 31, 2020 | 12.68% | 3.71% | 122.09 | 6.79 | 28.80 |
| 24. | Jan 31, 2021 | -8.61% | -1.11% | 104.88 | 4.93 | 22.73 |
| 25. | Feb 28, 2021 | -1.45% | 2.61% | 9.46 | 2.26 | -4.62 |
| 26. | Mar 31, 2021 | 0.29% | 4.24% | 1.79 | 9.85 | -4.20 |
| 27. | Apr 30, 2021 | 17.06% | 5.24% | 238.17 | 17.11 | 63.84 |
| 28. | May 31, 2021 | -2.64% | 0.55% | 18.17 | 0.31 | 2.38 |
| 29. | Jun 30, 2021 | 9.20% | 2.22% | 57.31 | 1.24 | 8.44 |
| 30. | Jul 31, 2021 | 7.81% | 2.27% | 38.22 | 1.37 | 7.23 |
| 31. | Aug 31, 2021 | 6.26% | 2.90% | 21.49 | 3.22 | 8.31 |
| 32. | Sep 30, 2021 | -5.64% | -4.76% | 52.82 | 34.37 | 42.61 |
| 33. | Oct 31, 2021 | 8.98% | 6.91% | 54.03 | 33.74 | 42.70 |
| 34. | Nov 30, 2021 | -10.19% | -0.83% | 139.59 | 3.76 | 22.91 |
| 35. | Dec 31, 2021 | 10.78% | 4.36% | 83.75 | 10.60 | 29.79 |
| 36. | Jan 31, 2022 | -20.91% | -5.26% | 507.80 | 40.51 | 143.42 |
| 37. | Feb 28, 2022 | 2.16% | -3.14% | 0.29 | 17.99 | -2.28 |
| 38. | Mar 31, 2022 | 3.91% | 3.58% | 5.21 | 6.11 | 5.64 |
| 39. | Apr 30, 2022 | -20.68% | -8.80% | 497.50 | 98.04 | 220.85 |
| 40. | May 31, 2022 | -4.87% | 0.01% | 42.25 | 1.21 | 7.15 |
| 41. | Jun 30, 2022 | -11.83% | -8.39% | 181.10 | 90.21 | 127.82 |
| 42. | Jul 31, 2022 | 14.68% | 9.11% | 170.32 | 64.09 | 104.48 |
| 43. | Aug 31, 2022 | -10.61% | -4.24% | 149.84 | 28.62 | 65.49 |
| 44. | Sep 30, 2022 | -8.89% | -9.34% | 110.71 | 109.11 | 109.91 |
| 45. | Oct 31, 2022 | 31.49% | 7.99% | 891.95 | 47.34 | 205.49 |
| 46. | Nov 30, 2022 | 9.71% | 5.38% | 65.25 | 18.23 | 34.49 |
| 47. | Dec 31, 2022 | -1.86% | -5.90% | 12.19 | 49.04 | 24.45 |
| 48. | Jan 31, 2023 | -7.41% | 6.18% | 81.65 | 25.70 | -45.81 |
| 49. | Feb 28, 2023 | -6.63% | -2.61% | 68.25 | 13.82 | 30.71 |
| 50. | Mar 31, 2023 | 11.37% | 3.51% | 94.91 | 5.76 | 23.37 |
| 51. | Apr 30, 2023 | 17.91% | 1.46% | 265.07 | 0.13 | 5.83 |
| 52. | May 31, 2023 | 2.20% | 0.25% | 0.33 | 0.74 | -0.49 |
| 53. | Jun 30, 2023 | 11.08% | 4.71% | 89.30 | 13.02 | 34.10 |
| 54. | Jul 31, 2023 | -5.13% | 4.85% | 45.65 | 13.99 | -25.27 |
| 55. | Aug 31, 2023 | -3.61% | -1.77% | 27.46 | 8.28 | 15.08 |
| 56. | Sep 30, 2023 | -6.52% | -4.87% | 66.39 | 35.73 | 48.71 |
| 57. | Oct 31, 2023 | -10.29% | -2.20% | 141.97 | 10.92 | 39.36 |
| 58. | Nov 30, 2023 | 18.54% | 8.92% | 286.10 | 61.03 | 132.14 |
| 59. | Dec 31, 2023 | 8.53% | 4.42% | 47.67 | 11.00 | 22.90 |
| Total (Σ): | 6,085.09 | 1,634.30 | 2,217.97 | |||
Show all
VarianceISRG = Σ(RISRG,t–RISRG)2 ÷ (59 – 1)
= 6,085.09 ÷ (59 – 1)
= 104.92
VarianceS&P 500 = Σ(RS&P 500,t–RS&P 500)2 ÷ (59 – 1)
= 1,634.30 ÷ (59 – 1)
= 28.18
CovarianceISRG, S&P 500 = Σ(RISRG,t–RISRG)×(RS&P 500,t–RS&P 500) ÷ (59 – 1)
= 2,217.97 ÷ (59 – 1)
= 38.24
Systematic Risk (β) Estimation
| VarianceISRG | 104.92 |
| VarianceS&P 500 | 28.18 |
| CovarianceISRG, S&P 500 | 38.24 |
| Correlation coefficientISRG, S&P 5001 | 0.70 |
| βISRG2 | 1.36 |
| αISRG3 | 0.13% |
Calculations
1 Correlation coefficientISRG, S&P 500
= CovarianceISRG, S&P 500 ÷ (Standard deviationISRG × Standard deviationS&P 500)
= 38.24 ÷ (10.24% × 5.31%)
= 0.70
2 βISRG
= CovarianceISRG, S&P 500 ÷ VarianceS&P 500
= 38.24 ÷ 28.18
= 1.36
3 αISRG
= AverageISRG – βISRG × AverageS&P 500
= 1.63% – 1.36 × 1.11%
= 0.13%
Expected Rate of Return
| Assumptions | ||
| Rate of return on LT Treasury Composite1 | RF | 4.67% |
| Expected rate of return on market portfolio2 | E(RM) | 13.79% |
| Systematic risk (β) of Intuitive Surgical Inc. common stock | βISRG | 1.36 |
| Expected rate of return on Intuitive Surgical Inc. common stock3 | E(RISRG) | 17.04% |
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(RISRG) = RF + βISRG [E(RM) – RF]
= 4.67% + 1.36 [13.79% – 4.67%]
= 17.04%