Goal

Simulate future portfolio returns

five stocks: “SPY”, “EFA”, “IJS”, “EEM”, “AGG”

market: “SPY”

from 2012-12-31 to 2017-12-31

1 Import stock prices

2 Convert prices to returns

3 Assign a weight to each asset

## [1] "AGG" "EEM" "EFA" "IJS" "SPY"
## [1] 0.25 0.25 0.20 0.20 0.10
## # A tibble: 5 × 2
##   symbols weights
##   <chr>     <dbl>
## 1 AGG        0.25
## 2 EEM        0.25
## 3 EFA        0.2 
## 4 IJS        0.2 
## 5 SPY        0.1

4 Build a portfolio

## # A tibble: 60 × 2
##    date        returns
##    <date>        <dbl>
##  1 2013-01-31  0.0204 
##  2 2013-02-28 -0.00239
##  3 2013-03-28  0.0121 
##  4 2013-04-30  0.0174 
##  5 2013-05-31 -0.0128 
##  6 2013-06-28 -0.0247 
##  7 2013-07-31  0.0321 
##  8 2013-08-30 -0.0224 
##  9 2013-09-30  0.0511 
## 10 2013-10-31  0.0301 
## # ℹ 50 more rows

5 Simulating growth of a dollar

## [1] 0.005899133
## [1] 0.02347492
##   [1]  1.796280e-02  1.770971e-02 -1.836576e-02  3.150785e-02 -2.828874e-02
##   [6] -7.742381e-03  4.154660e-03  4.201184e-02 -5.240419e-04  7.020332e-03
##  [11] -6.477951e-03 -1.349972e-03 -8.791242e-03 -7.957506e-03 -2.084662e-02
##  [16]  2.142265e-02 -2.185133e-02 -7.577245e-03  6.830754e-03 -1.608584e-02
##  [21] -1.295048e-03 -2.123194e-02 -1.157223e-02 -2.621031e-02 -4.597178e-03
##  [26]  1.535860e-03  1.078317e-02 -1.536779e-02  6.139537e-03  1.434121e-02
##  [31]  2.057349e-03 -1.450976e-02  6.528629e-03 -1.556314e-02 -4.435468e-02
##  [36]  5.605628e-03  4.067641e-02 -1.316802e-02  2.316397e-02 -2.914211e-02
##  [41]  1.680483e-02  2.196814e-02  8.959433e-03  1.292516e-02 -1.271757e-03
##  [46]  4.424042e-02  7.933548e-03  3.445974e-02 -9.545859e-03  7.008307e-03
##  [51]  2.408388e-02 -1.022125e-02 -6.571631e-03  1.302089e-02  2.602339e-02
##  [56] -1.781358e-02  3.822972e-02  2.964508e-02  3.960641e-04  3.210430e-02
##  [61] -6.860796e-03  3.683711e-02 -2.957210e-02  3.007677e-03  2.340698e-02
##  [66]  5.078404e-03 -1.370519e-02 -1.490582e-02  1.829093e-02 -3.827953e-02
##  [71]  3.145058e-02  1.465802e-02 -1.406893e-02 -8.418543e-03  3.392716e-02
##  [76] -4.739901e-03 -3.092025e-02  1.018527e-03  5.307102e-03 -1.724829e-03
##  [81] -1.538037e-03 -7.197898e-03  2.066451e-02  4.072290e-02  7.016841e-02
##  [86]  1.990194e-02  4.150660e-02  4.370418e-02 -1.472707e-02 -9.746480e-03
##  [91] -7.700122e-03  5.942837e-04  3.855307e-03  4.156732e-03  2.011593e-02
##  [96] -5.718786e-02 -6.660392e-03  6.681213e-02 -1.367422e-05  3.686283e-02
## [101]  1.473433e-02 -1.023049e-02 -3.189591e-03 -1.502908e-02 -6.325350e-04
## [106] -3.769110e-03 -3.302310e-02  1.824293e-02 -3.537872e-02 -1.531755e-02
## [111]  1.500933e-03 -1.059760e-02 -1.409365e-02 -5.811393e-03  7.685699e-04
## [116] -1.076433e-02  1.578144e-03 -4.543568e-03  4.201280e-03  4.337425e-02
## # A tibble: 121 × 1
##    returns
##      <dbl>
##  1   1    
##  2   1.02 
##  3   1.02 
##  4   0.982
##  5   1.03 
##  6   0.972
##  7   0.992
##  8   1.00 
##  9   1.04 
## 10   0.999
## # ℹ 111 more rows
## # A tibble: 121 × 1
##    growth
##     <dbl>
##  1   1   
##  2   1.02
##  3   1.04
##  4   1.02
##  5   1.05
##  6   1.02
##  7   1.01
##  8   1.02
##  9   1.06
## 10   1.06
## # ℹ 111 more rows
## [1] 3.620798

6 Simulation function

## # A tibble: 121 × 1
##    growth
##     <dbl>
##  1  1    
##  2  1.02 
##  3  0.997
##  4  0.994
##  5  1.02 
##  6  1.03 
##  7  1.02 
##  8  1.03 
##  9  1.07 
## 10  1.11 
## # ℹ 111 more rows

7 Running multiple simulations

##  sim1  sim2  sim3  sim4  sim5  sim6  sim7  sim8  sim9 sim10 sim11 sim12 sim13 
##     1     1     1     1     1     1     1     1     1     1     1     1     1 
## sim14 sim15 sim16 sim17 sim18 sim19 sim20 sim21 sim22 sim23 sim24 sim25 sim26 
##     1     1     1     1     1     1     1     1     1     1     1     1     1 
## sim27 sim28 sim29 sim30 sim31 sim32 sim33 sim34 sim35 sim36 sim37 sim38 sim39 
##     1     1     1     1     1     1     1     1     1     1     1     1     1 
## sim40 sim41 sim42 sim43 sim44 sim45 sim46 sim47 sim48 sim49 sim50 sim51 
##     1     1     1     1     1     1     1     1     1     1     1     1
## # A tibble: 6,171 × 3
##    month sim   growth
##    <int> <chr>  <dbl>
##  1     1 sim1       1
##  2     1 sim2       1
##  3     1 sim3       1
##  4     1 sim4       1
##  5     1 sim5       1
##  6     1 sim6       1
##  7     1 sim7       1
##  8     1 sim8       1
##  9     1 sim9       1
## 10     1 sim10      1
## # ℹ 6,161 more rows
##  0.5%  2.5%   25%   50%   75% 97.5% 99.5% 
##  1.02  1.22  1.64  1.87  2.30  3.13  3.16

8 Visualizing simulations with ggplot

## # A tibble: 1 × 3
##     max median   min
##   <dbl>  <dbl> <dbl>
## 1  3.16   1.87 0.969