# Load packages
library(tidyverse)
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library(tidyquant)
## Registered S3 method overwritten by 'quantmod':
##   method            from
##   as.zoo.data.frame zoo 
## ── Attaching core tidyquant packages ─────────────────────── tidyquant 1.0.11 ──
## ✔ PerformanceAnalytics 2.0.8      ✔ TTR                  0.24.4
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## ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors

1 Get stock prices and convert to returns

Ra <- c("PLTR", "BOW", "SOFI") %>%
    tq_get(get  = "stock.prices",
           from = "2022-01-01") %>%
    group_by(symbol) %>%
    tq_transmute(select     = adjusted, 
                 mutate_fun = periodReturn, 
                 period     = "monthly", 
                 col_rename = "Ra")
Ra
## # A tibble: 110 × 3
## # Groups:   symbol [3]
##    symbol date            Ra
##    <chr>  <date>       <dbl>
##  1 PLTR   2022-01-31 -0.260 
##  2 PLTR   2022-02-28 -0.136 
##  3 PLTR   2022-03-31  0.159 
##  4 PLTR   2022-04-29 -0.243 
##  5 PLTR   2022-05-31 -0.165 
##  6 PLTR   2022-06-30  0.0449
##  7 PLTR   2022-07-29  0.141 
##  8 PLTR   2022-08-31 -0.254 
##  9 PLTR   2022-09-30  0.0531
## 10 PLTR   2022-10-31  0.0812
## # ℹ 100 more rows

2 Get baseline and convert to returns

Rb <- "^IXIC" %>%
    tq_get(get  = "stock.prices",
           from = "2022-01-01") %>%
    tq_transmute(select     = adjusted, 
                 mutate_fun = periodReturn, 
                 period     = "monthly", 
                 col_rename = "Rb")
Rb
## # A tibble: 46 × 2
##    date            Rb
##    <date>       <dbl>
##  1 2022-01-31 -0.101 
##  2 2022-02-28 -0.0343
##  3 2022-03-31  0.0341
##  4 2022-04-29 -0.133 
##  5 2022-05-31 -0.0205
##  6 2022-06-30 -0.0871
##  7 2022-07-29  0.123 
##  8 2022-08-31 -0.0464
##  9 2022-09-30 -0.105 
## 10 2022-10-31  0.0390
## # ℹ 36 more rows

3 Join the two tables

RaRb <- left_join(Ra, Rb, by = c("date" = "date"))
RaRb
## # A tibble: 110 × 4
## # Groups:   symbol [3]
##    symbol date            Ra      Rb
##    <chr>  <date>       <dbl>   <dbl>
##  1 PLTR   2022-01-31 -0.260  -0.101 
##  2 PLTR   2022-02-28 -0.136  -0.0343
##  3 PLTR   2022-03-31  0.159   0.0341
##  4 PLTR   2022-04-29 -0.243  -0.133 
##  5 PLTR   2022-05-31 -0.165  -0.0205
##  6 PLTR   2022-06-30  0.0449 -0.0871
##  7 PLTR   2022-07-29  0.141   0.123 
##  8 PLTR   2022-08-31 -0.254  -0.0464
##  9 PLTR   2022-09-30  0.0531 -0.105 
## 10 PLTR   2022-10-31  0.0812  0.0390
## # ℹ 100 more rows

4 Calculate CAPM

RaRb_capm <- RaRb %>%
    tq_performance(Ra = Ra, 
                   Rb = Rb, 
                   performance_fun = table.CAPM)
## Registered S3 method overwritten by 'robustbase':
##   method          from     
##   hatvalues.lmrob RobStatTM
RaRb_capm
## # A tibble: 3 × 18
## # Groups:   symbol [3]
##   symbol ActivePremium  Alpha AlphaRobust AnnualizedAlpha   Beta `Beta-`
##   <chr>          <dbl>  <dbl>       <dbl>           <dbl>  <dbl>   <dbl>
## 1 PLTR          0.717  0.0528      0.0183           0.855  1.92    0.878
## 2 BOW          -0.266  0.0281      0.0189           0.394 -0.846  -1.67 
## 3 SOFI          0.0692 0.0122      0.0027           0.157  2.00    3.47 
## # ℹ 11 more variables: `Beta-Robust` <dbl>, `Beta+` <dbl>, `Beta+Robust` <dbl>,
## #   BetaRobust <dbl>, Correlation <dbl>, `Correlationp-value` <dbl>,
## #   InformationRatio <dbl>, `R-squared` <dbl>, `R-squaredRobust` <dbl>,
## #   TrackingError <dbl>, TreynorRatio <dbl>