#load Packages
library(tidyquant)
library(tidyverse)

1 Get Stock prices and convert to returns

Ra <- c("WMT", "PG", "JNJ") %>%
    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: 27 × 3
## # Groups:   symbol [3]
##    symbol date             Ra
##    <chr>  <date>        <dbl>
##  1 WMT    2022-01-31 -0.0335 
##  2 WMT    2022-02-28 -0.0333 
##  3 WMT    2022-03-31  0.106  
##  4 WMT    2022-04-29  0.0273 
##  5 WMT    2022-05-31 -0.156  
##  6 WMT    2022-06-30 -0.0548 
##  7 WMT    2022-07-29  0.0861 
##  8 WMT    2022-08-31  0.00816
##  9 WMT    2022-09-21  0.0167 
## 10 PG     2022-01-31 -0.00972
## # … with 17 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: 9 × 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 2022-09-21 -0.0504

3 Join the two data tables

RaRb <- left_join(Ra, Rb, by = c("date" = "date"))
RaRb
## # A tibble: 27 × 4
## # Groups:   symbol [3]
##    symbol date             Ra      Rb
##    <chr>  <date>        <dbl>   <dbl>
##  1 WMT    2022-01-31 -0.0335  -0.101 
##  2 WMT    2022-02-28 -0.0333  -0.0343
##  3 WMT    2022-03-31  0.106    0.0341
##  4 WMT    2022-04-29  0.0273  -0.133 
##  5 WMT    2022-05-31 -0.156   -0.0205
##  6 WMT    2022-06-30 -0.0548  -0.0871
##  7 WMT    2022-07-29  0.0861   0.123 
##  8 WMT    2022-08-31  0.00816 -0.0464
##  9 WMT    2022-09-21  0.0167  -0.0504
## 10 PG     2022-01-31 -0.00972 -0.101 
## # … with 17 more rows

4 Calculate CAPM

Which Stock has positivly skewed distribution of returns

Proctor and gamble and Johnson and Johnson have positivly skewed distribution of returns