Chapter 3: Portfolio Returns

Construct an equal-weighted (EW) and value-weighted (VW) portfolio, consisting of AMZN, MSFT, AAPL, and, TSLA.

In this section, prepare an object, port, which will be used later to build EW and VW portfolio.

Step 0: Import Price Data

# To clean up the memory of your current R session run the following line
rm(list=ls(all=TRUE))

library(quantmod)
library(xts)

#Importing Price Data
data.AMZN <- getSymbols("AMZN", from = "2016-12-30", to = "2017-07-01", auto.assign = FALSE)
data.MSFT <- getSymbols("MSFT", from = "2016-12-30", to = "2017-07-01", auto.assign = FALSE)
data.AAPL <- getSymbols("AAPL", from = "2016-12-30", to = "2017-07-01", auto.assign = FALSE)
data.TSLA <- getSymbols("TSLA", from = "2016-12-30", to = "2017-07-01", auto.assign = FALSE)
#to = "2017-06-30" in the book was replaced by to = "2017-07-01"
#B/c that code doesn't produce the output that includes stock price of 2013-12-31the date. 

Step 1: Importing the Price Data

data.AMZN[c(1:3, nrow(data.AMZN)), ]
##            AMZN.Open AMZN.High AMZN.Low AMZN.Close AMZN.Volume
## 2016-12-30    766.47    767.40   748.28     749.87     4139400
## 2017-01-03    757.92    758.76   747.70     753.67     3521100
## 2017-01-04    758.39    759.68   754.20     757.18     2510500
## 2017-06-30    980.12    983.47   967.61     968.00     3390300
##            AMZN.Adjusted
## 2016-12-30        749.87
## 2017-01-03        753.67
## 2017-01-04        757.18
## 2017-06-30        968.00
data.MSFT[c(1:3, nrow(data.MSFT)), ]
##            MSFT.Open MSFT.High MSFT.Low MSFT.Close MSFT.Volume
## 2016-12-30    64.366    64.396   63.415      62.14    25579900
## 2017-01-03    64.192    64.243   63.517      62.58    20694100
## 2017-01-04    63.875    64.151   63.507      62.30    21340000
## 2017-06-30    69.494    70.100   69.453      68.93    24161100
##            MSFT.Adjusted
## 2016-12-30      60.78280
## 2017-01-03      61.21319
## 2017-01-04      60.93930
## 2017-06-30      68.22208
data.AAPL[c(1:3, nrow(data.AAPL)), ]
##            AAPL.Open AAPL.High AAPL.Low AAPL.Close AAPL.Volume
## 2016-12-30   118.526   119.085  117.286     115.82    30586300
## 2017-01-03   117.662   118.201  116.605     116.15    28781900
## 2017-01-04   117.713   118.384  117.611     116.02    21118100
## 2017-06-30   145.539   146.052  144.864     144.02    23024100
##            AAPL.Adjusted
## 2016-12-30      113.9870
## 2017-01-03      114.3118
## 2017-01-04      114.1838
## 2017-06-30      142.9428
data.TSLA[c(1:3, nrow(data.TSLA)), ]
##            TSLA.Open TSLA.High TSLA.Low TSLA.Close TSLA.Volume
## 2016-12-30    216.30    217.50   211.68     213.69     4642600
## 2017-01-03    214.86    220.33   210.96     216.99     5923300
## 2017-01-04    214.75    228.00   214.31     226.99    11213500
## 2017-06-30    363.71    366.77   359.62     361.61     5848500
##            TSLA.Adjusted
## 2016-12-30        213.69
## 2017-01-03        216.99
## 2017-01-04        226.99
## 2017-06-30        361.61

Step 2: Create Object with Only the Relevant Data

port <- data.AMZN[, c(4, 6)]
port <- merge(port, data.MSFT[, c(4, 6)])
port <- merge(port, data.AAPL[, c(4, 6)])
port <- merge(port, data.TSLA[, c(4, 6)])
#port <- cbind(port, data.MSFT[, c(4, 6)], data.AAPL[, c(4, 6)], data.TSLA[, c(4, 6)])
port[c(1:3, nrow(port)), ]
##            AMZN.Close AMZN.Adjusted MSFT.Close MSFT.Adjusted AAPL.Close
## 2016-12-30     749.87        749.87      62.14      60.78280     115.82
## 2017-01-03     753.67        753.67      62.58      61.21319     116.15
## 2017-01-04     757.18        757.18      62.30      60.93930     116.02
## 2017-06-30     968.00        968.00      68.93      68.22208     144.02
##            AAPL.Adjusted TSLA.Close TSLA.Adjusted
## 2016-12-30      113.9870     213.69        213.69
## 2017-01-03      114.3118     216.99        216.99
## 2017-01-04      114.1838     226.99        226.99
## 2017-06-30      142.9428     361.61        361.61

Step 3: Calculate Returns of Each Security

port$AMZN.ret <- Delt(port$AMZN.Adjusted)
port$MSFT.ret <- Delt(port$MSFT.Adjusted)
port$AAPL.ret <- Delt(port$AAPL.Adjusted)
port$TSLA.ret <- Delt(port$TSLA.Adjusted)
port[c(1:3, nrow(port)), ]
##            AMZN.Close AMZN.Adjusted MSFT.Close MSFT.Adjusted AAPL.Close
## 2016-12-30     749.87        749.87      62.14      60.78280     115.82
## 2017-01-03     753.67        753.67      62.58      61.21319     116.15
## 2017-01-04     757.18        757.18      62.30      60.93930     116.02
## 2017-06-30     968.00        968.00      68.93      68.22208     144.02
##            AAPL.Adjusted TSLA.Close TSLA.Adjusted     AMZN.ret
## 2016-12-30      113.9870     213.69        213.69           NA
## 2017-01-03      114.3118     216.99        216.99  0.005067529
## 2017-01-04      114.1838     226.99        226.99  0.004657224
## 2017-06-30      142.9428     361.61        361.61 -0.008125576
##                MSFT.ret     AAPL.ret    TSLA.ret
## 2016-12-30           NA           NA          NA
## 2017-01-03  0.007080902  0.002849238 0.015442945
## 2017-01-04 -0.004474330 -0.001119264 0.046085072
## 2017-06-30  0.006424249  0.002366525 0.002383881

Step 4: Convert to data.frame Object and Subset Data

port <- cbind(index(port), data.frame(port))
names(port)[1] <- "date"
port[c(1:3, nrow(port)), ]
##                  date AMZN.Close AMZN.Adjusted MSFT.Close MSFT.Adjusted
## 2016-12-30 2016-12-30     749.87        749.87      62.14      60.78280
## 2017-01-03 2017-01-03     753.67        753.67      62.58      61.21319
## 2017-01-04 2017-01-04     757.18        757.18      62.30      60.93930
## 2017-06-30 2017-06-30     968.00        968.00      68.93      68.22208
##            AAPL.Close AAPL.Adjusted TSLA.Close TSLA.Adjusted     AMZN.ret
## 2016-12-30     115.82      113.9870     213.69        213.69           NA
## 2017-01-03     116.15      114.3118     216.99        216.99  0.005067529
## 2017-01-04     116.02      114.1838     226.99        226.99  0.004657224
## 2017-06-30     144.02      142.9428     361.61        361.61 -0.008125576
##                MSFT.ret     AAPL.ret    TSLA.ret
## 2016-12-30           NA           NA          NA
## 2017-01-03  0.007080902  0.002849238 0.015442945
## 2017-01-04 -0.004474330 -0.001119264 0.046085072
## 2017-06-30  0.006424249  0.002366525 0.002383881

port <- subset(port,
               port$date >= "2016-12-30" &
               port$date <= "2017-12-31")
port[c(1:3, nrow(port)), ]
##                  date AMZN.Close AMZN.Adjusted MSFT.Close MSFT.Adjusted
## 2016-12-30 2016-12-30     749.87        749.87      62.14      60.78280
## 2017-01-03 2017-01-03     753.67        753.67      62.58      61.21319
## 2017-01-04 2017-01-04     757.18        757.18      62.30      60.93930
## 2017-06-30 2017-06-30     968.00        968.00      68.93      68.22208
##            AAPL.Close AAPL.Adjusted TSLA.Close TSLA.Adjusted     AMZN.ret
## 2016-12-30     115.82      113.9870     213.69        213.69           NA
## 2017-01-03     116.15      114.3118     216.99        216.99  0.005067529
## 2017-01-04     116.02      114.1838     226.99        226.99  0.004657224
## 2017-06-30     144.02      142.9428     361.61        361.61 -0.008125576
##                MSFT.ret     AAPL.ret    TSLA.ret
## 2016-12-30           NA           NA          NA
## 2017-01-03  0.007080902  0.002849238 0.015442945
## 2017-01-04 -0.004474330 -0.001119264 0.046085072
## 2017-06-30  0.006424249  0.002366525 0.002383881

3.3.1 Equal-Weighted Portfolio

considerd as an approach to capture the small capitalization stock premeum (the belief that small cap stock yield higher returns over larger cap stocks) An example is the S&P 500 Equal Weight Index

Step 1: Keep Only Variables We Need to Construct EW Portfolio

ewport <- port[, c(1, 10:13)]
ewport[c(1:3, nrow(ewport)), ]
##                  date     AMZN.ret     MSFT.ret     AAPL.ret    TSLA.ret
## 2016-12-30 2016-12-30           NA           NA           NA          NA
## 2017-01-03 2017-01-03  0.005067529  0.007080902  0.002849238 0.015442945
## 2017-01-04 2017-01-04  0.004657224 -0.004474330 -0.001119264 0.046085072
## 2017-06-30 2017-06-30 -0.008125576  0.006424249  0.002366525 0.002383881

names(ewport)[2:5] <- c("AMZN", "MSFT", "AAPL", "TSLA")
rownames(ewport) <- seq(1, nrow(ewport), 1)
ewport[c(1:3, nrow(ewport)), ]
##           date         AMZN         MSFT         AAPL        TSLA
## 1   2016-12-30           NA           NA           NA          NA
## 2   2017-01-03  0.005067529  0.007080902  0.002849238 0.015442945
## 3   2017-01-04  0.004657224 -0.004474330 -0.001119264 0.046085072
## 126 2017-06-30 -0.008125576  0.006424249  0.002366525 0.002383881

Step 2: Convert Net Returns to Gross Returns

ewport[2:5] <- ewport[2:5] + 1
ewport[c(1:3, nrow(ewport)), ]
##           date      AMZN      MSFT      AAPL     TSLA
## 1   2016-12-30        NA        NA        NA       NA
## 2   2017-01-03 1.0050675 1.0070809 1.0028492 1.015443
## 3   2017-01-04 1.0046572 0.9955257 0.9988807 1.046085
## 126 2017-06-30 0.9918744 1.0064242 1.0023665 1.002384

Step 3: Calculate EW Portfolio Values for 1Q 2013

# Subset ewport by data from December 30, 2016 to March 31, 2017
ewq1 <- subset(ewport,
               ewport$date >= "2016-12-30" &
               ewport$date <= "2017-03-31")
ewq1[c(1:3, nrow(ewq1)), ]
##          date     AMZN      MSFT      AAPL     TSLA
## 1  2016-12-30       NA        NA        NA       NA
## 2  2017-01-03 1.005068 1.0070809 1.0028492 1.015443
## 3  2017-01-04 1.004657 0.9955257 0.9988807 1.046085
## 63 2017-03-31 1.011639 1.0022828 0.9981242 1.001367

# Calculate the cumulative gross returns fro each security for Q1
ewq1[1, 2:5] <- 1
ewq1[2:5] <- cumprod(ewq1[2:5])
ewq1[c(1:3, nrow(ewq1)), ]
##          date     AMZN     MSFT     AAPL     TSLA
## 1  2016-12-30 1.000000 1.000000 1.000000 1.000000
## 2  2017-01-03 1.005068 1.007081 1.002849 1.015443
## 3  2017-01-04 1.009748 1.002575 1.001727 1.062240
## 63 2017-03-31 1.182258 1.066290 1.245751 1.302354

# Calculate the index value for each security for Q1
num.sec <- 4
ewq1$AMZN.ind <- ewq1$AMZN / num.sec
ewq1$MSFT.ind <- ewq1$MSFT / num.sec
ewq1$AAPL.ind <- ewq1$AAPL / num.sec
ewq1$TSLA.ind <- ewq1$TSLA / num.sec
ewq1[c(1:3, nrow(ewq1)), ]
##          date     AMZN     MSFT     AAPL     TSLA  AMZN.ind  MSFT.ind
## 1  2016-12-30 1.000000 1.000000 1.000000 1.000000 0.2500000 0.2500000
## 2  2017-01-03 1.005068 1.007081 1.002849 1.015443 0.2512669 0.2517702
## 3  2017-01-04 1.009748 1.002575 1.001727 1.062240 0.2524371 0.2506437
## 63 2017-03-31 1.182258 1.066290 1.245751 1.302354 0.2955646 0.2665726
##     AAPL.ind  TSLA.ind
## 1  0.2500000 0.2500000
## 2  0.2507123 0.2538607
## 3  0.2504317 0.2655599
## 63 0.3114377 0.3255885

# Calculate the agrregate portfolio value on each day
q1.val <- data.frame(rowSums(ewq1[, 6:9]))
q1.val[c(1:3, nrow(q1.val)), ]
## [1] 1.000000 1.007610 1.019072 1.199163
names(q1.val) <- paste("port.val")
q1.val$date <- ewq1$date
q1.val[c(1:3, nrow(q1.val)),]
##    port.val       date
## 1  1.000000 2016-12-30
## 2  1.007610 2017-01-03
## 3  1.019072 2017-01-04
## 63 1.199163 2017-03-31

# Pass the aggregate portfolio value at the end of Q1 to Q2
q2.inv <- q1.val[nrow(q1.val), 1]
q2.inv
## [1] 1.199163

Step 4: Calculate EW Portfolio Values for 2Q 2017

# Subset ewport by data from April 1, 2017 to June 30, 2017
ewq2 <- subset(ewport,
               ewport$date >= "2017-04-01" &
               ewport$date <= "2017-06-30")
ewq2[c(1:3, nrow(ewq2)), ]
##           date      AMZN      MSFT      AAPL      TSLA
## 64  2017-04-03 1.0056061 0.9952930 1.0002784 1.0726554
## 65  2017-04-04 1.0171843 1.0027460 1.0074461 1.0173523
## 66  2017-04-05 1.0027017 0.9974135 0.9948194 0.9713533
## 126 2017-06-30 0.9918744 1.0064242 1.0023665 1.0023839

# Calculate the cumulative gross returns fro each security for Q2
#ewq2[1, 2:5] <- 1 This is the difference from Q1
ewq2[2:5] <- cumprod(ewq2[2:5])
ewq2[c(1:3, nrow(ewq2)), ]
##           date     AMZN      MSFT     AAPL     TSLA
## 64  2017-04-03 1.005606 0.9952930 1.000278 1.072655
## 65  2017-04-04 1.022887 0.9980261 1.007727 1.091269
## 66  2017-04-05 1.025650 0.9954448 1.002506 1.060007
## 126 2017-06-30 1.091885 1.0526131 1.006644 1.299353

# Calculate the index value for each security for Q2
ewq2$AMZN.ind <- (q2.inv / num.sec) * ewq2$AMZN #a difference from Q1
ewq2$MSFT.ind <- (q2.inv / num.sec) * ewq2$MSFT 
ewq2$AAPL.ind <- (q2.inv / num.sec) * ewq2$AAPL
ewq2$TSLA.ind <- (q2.inv / num.sec) * ewq2$TSLA 
ewq2[c(1:3, nrow(ewq2)), ]
##           date     AMZN      MSFT     AAPL     TSLA  AMZN.ind  MSFT.ind
## 64  2017-04-03 1.005606 0.9952930 1.000278 1.072655 0.3014715 0.2983797
## 65  2017-04-04 1.022887 0.9980261 1.007727 1.091269 0.3066521 0.2991991
## 66  2017-04-05 1.025650 0.9954448 1.002506 1.060007 0.3074806 0.2984252
## 126 2017-06-30 1.091885 1.0526131 1.006644 1.299353 0.3273372 0.3155637
##      AAPL.ind  TSLA.ind
## 64  0.2998743 0.3215723
## 65  0.3021072 0.3271523
## 66  0.3005421 0.3177804
## 126 0.3017826 0.3895342

# Calculate the agrregate portfolio value on each day
q2.val <- data.frame(rowSums(ewq2[, 6:9]))
q2.val[c(1:3, nrow(q2.val)), ]
## [1] 1.221298 1.235111 1.224228 1.334218
names(q2.val) <- paste("port.val")
q2.val$date <- ewq2$date
q2.val[c(1:3, nrow(q2.val)), ]
##     port.val       date
## 64  1.221298 2017-04-03
## 65  1.235111 2017-04-04
## 66  1.224228 2017-04-05
## 126 1.334218 2017-06-30

#$1.121 at the end of Q1 and 1.125
#Means the portfolio grown from $1.121 at the end of Q1 to $1.125 at the end of Q2
#Note that it doesn't mean that the portfolio grew 12.5% during Q2 but 12.5% during Q1-Q2
#b/c this is a cumulative measure 

Step 7: Combine Quarterly EW Portfolio Values into One Data Object

ew.portval <- rbind(q1.val, q2.val)
ew.portval[c(1:3, nrow(ew.portval)), ]
##     port.val       date
## 1   1.000000 2016-12-30
## 2   1.007610 2017-01-03
## 3   1.019072 2017-01-04
## 126 1.334218 2017-06-30

3.3.2 Value-Weighted Portfolio

It’s considerd as an approach to track the changes in the size of the sector. Larger firms are given more weight in VW, whereas equal weights are given in EW portfolio. An example is the S&P 500 Index. It rebalances only at the beginning of each quarter.

Step 1: Keep Only Variables We Need to Construct EW Portfolio

vwport <- port[, c(1, 2, 4, 6, 8, 10:13)] #port is from 3.3 Constructing Benchmark Portfolio Returns
vwport[c(1:3, nrow(vwport)), ]
##                  date AMZN.Close MSFT.Close AAPL.Close TSLA.Close
## 2016-12-30 2016-12-30     749.87      62.14     115.82     213.69
## 2017-01-03 2017-01-03     753.67      62.58     116.15     216.99
## 2017-01-04 2017-01-04     757.18      62.30     116.02     226.99
## 2017-06-30 2017-06-30     968.00      68.93     144.02     361.61
##                AMZN.ret     MSFT.ret     AAPL.ret    TSLA.ret
## 2016-12-30           NA           NA           NA          NA
## 2017-01-03  0.005067529  0.007080902  0.002849238 0.015442945
## 2017-01-04  0.004657224 -0.004474330 -0.001119264 0.046085072
## 2017-06-30 -0.008125576  0.006424249  0.002366525 0.002383881
rownames(vwport) <- seq(1:nrow(vwport))
vwport[c(1:3, nrow(vwport)), ]
##           date AMZN.Close MSFT.Close AAPL.Close TSLA.Close     AMZN.ret
## 1   2016-12-30     749.87      62.14     115.82     213.69           NA
## 2   2017-01-03     753.67      62.58     116.15     216.99  0.005067529
## 3   2017-01-04     757.18      62.30     116.02     226.99  0.004657224
## 126 2017-06-30     968.00      68.93     144.02     361.61 -0.008125576
##         MSFT.ret     AAPL.ret    TSLA.ret
## 1             NA           NA          NA
## 2    0.007080902  0.002849238 0.015442945
## 3   -0.004474330 -0.001119264 0.046085072
## 126  0.006424249  0.002366525 0.002383881

Step 2: Convert Net Returns to Gross Returns

vwport$AMZN.ret <- vwport$AMZN.ret + 1
vwport$MSFT.ret <- vwport$MSFT.ret + 1
vwport$AAPL.ret <- vwport$AAPL.ret + 1
vwport$TSLA.ret <- vwport$TSLA.ret + 1
vwport[c(1:3, nrow(vwport)), ]
##           date AMZN.Close MSFT.Close AAPL.Close TSLA.Close  AMZN.ret
## 1   2016-12-30     749.87      62.14     115.82     213.69        NA
## 2   2017-01-03     753.67      62.58     116.15     216.99 1.0050675
## 3   2017-01-04     757.18      62.30     116.02     226.99 1.0046572
## 126 2017-06-30     968.00      68.93     144.02     361.61 0.9918744
##      MSFT.ret  AAPL.ret TSLA.ret
## 1          NA        NA       NA
## 2   1.0070809 1.0028492 1.015443
## 3   0.9955257 0.9988807 1.046085
## 126 1.0064242 1.0023665 1.002384

Step 3: Calculate the Market Capitalization of Each Security in the Portfolio

# Construct Series of Calendar Days
date <- seq(as.Date("2016-12-30"), as.Date("2017-12-31"), by = 1)
date <- data.frame(date)
date[c(1:3, nrow(date)), ]
## [1] "2016-12-30" "2016-12-31" "2017-01-01" "2017-12-31"

# Create Data Object with Daily Prices
PRICE.qtr <- vwport[, 1:5]
PRICE.qtr[c(1:3, nrow(PRICE.qtr)), ]
##           date AMZN.Close MSFT.Close AAPL.Close TSLA.Close
## 1   2016-12-30     749.87      62.14     115.82     213.69
## 2   2017-01-03     753.67      62.58     116.15     216.99
## 3   2017-01-04     757.18      62.30     116.02     226.99
## 126 2017-06-30     968.00      68.93     144.02     361.61

# Filling in Last Available Price on Non-trading Days
PRICE.qtr <- na.locf(merge(x = date, y = PRICE.qtr, by = "date", all.x = TRUE))
#all.x=T tells R to keep all the data in the "by" varialble that is available in x=date
#na.locf tells R to copy over the last available data in y 
#when there is a date in x that is not available in y
PRICE.qtr[c(1:3, nrow(PRICE.qtr)), ]
##           date AMZN.Close MSFT.Close AAPL.Close TSLA.Close
## 1   2016-12-30     749.87      62.14     115.82     213.69
## 2   2016-12-31     749.87      62.14     115.82     213.69
## 3   2017-01-01     749.87      62.14     115.82     213.69
## 367 2017-12-31     968.00      68.93     144.02     361.61

# Keep Only Prices at the End of Each Calendar Quarter
PRICE.qtr <- subset(PRICE.qtr,
                    PRICE.qtr$date == as.Date("2016-12-30") |
                    PRICE.qtr$date == as.Date("2017-03-31"))
PRICE.qtr
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close
## 1  2016-12-30     749.87      62.14     115.82     213.69
## 92 2017-03-31     886.54      65.86     143.66     278.30


# Obtain Share Outstanding Data from SEC Filings
#http://www.sec.gov/edgar/searchedgar/companysearch.html
#Interactive Data / Financial Statements / Condensed Consolidated Balance Sheets
PRICE.qtr$AMZN.shout <- c(477000000, 478000000)
PRICE.qtr$MSFT.shout <- c(7730000000, 7723000000)
PRICE.qtr$AAPL.shout <- c(5255423   , 5205815)
PRICE.qtr$TSLA.shout <- c(161561000, 164164000)
PRICE.qtr
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close AMZN.shout
## 1  2016-12-30     749.87      62.14     115.82     213.69   4.77e+08
## 92 2017-03-31     886.54      65.86     143.66     278.30   4.78e+08
##    MSFT.shout AAPL.shout TSLA.shout
## 1   7.730e+09    5255423  161561000
## 92  7.723e+09    5205815  164164000

# Calculate Market Capitalization of Each Security
str(PRICE.qtr)
## 'data.frame':    2 obs. of  9 variables:
##  $ date      : chr  "2016-12-30" "2017-03-31"
##  $ AMZN.Close: chr  " 749.87" " 886.54"
##  $ MSFT.Close: chr  "62.14" "65.86"
##  $ AAPL.Close: chr  "115.82" "143.66"
##  $ TSLA.Close: chr  "213.69" "278.30"
##  $ AMZN.shout: num  4.77e+08 4.78e+08
##  $ MSFT.shout: num  7.73e+09 7.72e+09
##  $ AAPL.shout: num  5255423 5205815
##  $ TSLA.shout: num  1.62e+08 1.64e+08
PRICE.qtr$date <- as.Date(PRICE.qtr$date)
PRICE.qtr$AMZN.Close <- as.numeric(PRICE.qtr$AMZN.Close)
PRICE.qtr$MSFT.Close <- as.numeric(PRICE.qtr$MSFT.Close)
PRICE.qtr$AAPL.Close <- as.numeric(PRICE.qtr$AAPL.Close)
PRICE.qtr$TSLA.Close <- as.numeric(PRICE.qtr$TSLA.Close)
str(PRICE.qtr)
## 'data.frame':    2 obs. of  9 variables:
##  $ date      : Date, format: "2016-12-30" "2017-03-31"
##  $ AMZN.Close: num  750 887
##  $ MSFT.Close: num  62.1 65.9
##  $ AAPL.Close: num  116 144
##  $ TSLA.Close: num  214 278
##  $ AMZN.shout: num  4.77e+08 4.78e+08
##  $ MSFT.shout: num  7.73e+09 7.72e+09
##  $ AAPL.shout: num  5255423 5205815
##  $ TSLA.shout: num  1.62e+08 1.64e+08

weights <- PRICE.qtr
weights$AMZN.mcap <- weights$AMZN.Close * weights$AMZN.shout
weights$MSFT.mcap <- weights$MSFT.Close * weights$MSFT.shout
weights$AAPL.mcap <- weights$AAPL.Close * weights$AAPL.shout
weights$TSLA.mcap <- weights$TSLA.Close * weights$TSLA.shout
weights
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close AMZN.shout
## 1  2016-12-30     749.87      62.14     115.82     213.69   4.77e+08
## 92 2017-03-31     886.54      65.86     143.66     278.30   4.78e+08
##    MSFT.shout AAPL.shout TSLA.shout    AMZN.mcap    MSFT.mcap AAPL.mcap
## 1   7.730e+09    5255423  161561000 357687990000 480342200000 608683092
## 92  7.723e+09    5205815  164164000 423766120000 508636780000 747867383
##      TSLA.mcap
## 1  34523970090
## 92 45686841200

# Calculate Quarter-end Aggregate Market Capitalization
weights$tot.mcap <- rowSums(weights[,10:13])
weights
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close AMZN.shout
## 1  2016-12-30     749.87      62.14     115.82     213.69   4.77e+08
## 92 2017-03-31     886.54      65.86     143.66     278.30   4.78e+08
##    MSFT.shout AAPL.shout TSLA.shout    AMZN.mcap    MSFT.mcap AAPL.mcap
## 1   7.730e+09    5255423  161561000 357687990000 480342200000 608683092
## 92  7.723e+09    5205815  164164000 423766120000 508636780000 747867383
##      TSLA.mcap     tot.mcap
## 1  34523970090 873162843182
## 92 45686841200 978837608583

Step 4: Calculate Quarter-end Weights of Each Security in the Portfolio

weights$AMZN.wgt <- weights$AMZN.mcap / weights$tot.mcap
weights$MSFT.wgt <- weights$MSFT.mcap / weights$tot.mcap
weights$AAPL.wgt <- weights$AAPL.mcap / weights$tot.mcap
weights$TSLA.wgt <- weights$TSLA.mcap / weights$tot.mcap
weights
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close AMZN.shout
## 1  2016-12-30     749.87      62.14     115.82     213.69   4.77e+08
## 92 2017-03-31     886.54      65.86     143.66     278.30   4.78e+08
##    MSFT.shout AAPL.shout TSLA.shout    AMZN.mcap    MSFT.mcap AAPL.mcap
## 1   7.730e+09    5255423  161561000 357687990000 480342200000 608683092
## 92  7.723e+09    5205815  164164000 423766120000 508636780000 747867383
##      TSLA.mcap     tot.mcap  AMZN.wgt  MSFT.wgt     AAPL.wgt   TSLA.wgt
## 1  34523970090 873162843182 0.4096464 0.5501175 0.0006971015 0.03953898
## 92 45686841200 978837608583 0.4329279 0.5196335 0.0007640362 0.04667459

weights <- weights[, c(1, 15:18)]
weights
##          date  AMZN.wgt  MSFT.wgt     AAPL.wgt   TSLA.wgt
## 1  2016-12-30 0.4096464 0.5501175 0.0006971015 0.03953898
## 92 2017-03-31 0.4329279 0.5196335 0.0007640362 0.04667459

weights[1, "date"] <- weights[1, "date"]+2 

weights[2, "date"] <- weights[2, "date"]+1 #since the weights are applicable at the start of the next Q
weights
##          date  AMZN.wgt  MSFT.wgt     AAPL.wgt   TSLA.wgt
## 1  2017-01-01 0.4096464 0.5501175 0.0006971015 0.03953898
## 92 2017-04-01 0.4329279 0.5196335 0.0007640362 0.04667459

Step 5: Calculate the Quarterly VW Portfolio Values

q1.vw.wgt <- subset(weights, date == "2017-01-01") #I'm not sure why author took the long way
q2.vw.wgt <- subset(weights, date == "2017-04-01")
q1.vw.wgt
##         date  AMZN.wgt  MSFT.wgt     AAPL.wgt   TSLA.wgt
## 1 2017-01-01 0.4096464 0.5501175 0.0006971015 0.03953898
q2.vw.wgt
##          date  AMZN.wgt  MSFT.wgt     AAPL.wgt   TSLA.wgt
## 92 2017-04-01 0.4329279 0.5196335 0.0007640362 0.04667459

Step 7: Calculate VW Portfolio Values for 1Q 2013

vw.q1 <- subset(vwport,
                vwport$date >= as.Date("2016-12-30") &
                vwport$date <= as.Date("2017-03-31"))
vw.q1[c(1:3, nrow(vw.q1)), ]
##          date AMZN.Close MSFT.Close AAPL.Close TSLA.Close AMZN.ret
## 1  2016-12-30     749.87      62.14     115.82     213.69       NA
## 2  2017-01-03     753.67      62.58     116.15     216.99 1.005068
## 3  2017-01-04     757.18      62.30     116.02     226.99 1.004657
## 63 2017-03-31     886.54      65.86     143.66     278.30 1.011639
##     MSFT.ret  AAPL.ret TSLA.ret
## 1         NA        NA       NA
## 2  1.0070809 1.0028492 1.015443
## 3  0.9955257 0.9988807 1.046085
## 63 1.0022828 0.9981242 1.001367

vw.q1 <- vw.q1[, c(1, 6:9)]
vw.q1[c(1:3, nrow(vw.q1)), ]
##          date AMZN.ret  MSFT.ret  AAPL.ret TSLA.ret
## 1  2016-12-30       NA        NA        NA       NA
## 2  2017-01-03 1.005068 1.0070809 1.0028492 1.015443
## 3  2017-01-04 1.004657 0.9955257 0.9988807 1.046085
## 63 2017-03-31 1.011639 1.0022828 0.9981242 1.001367

names(vw.q1)[2:5] <- paste(c("AMZN", "MSFT", "AAPL", "TSLA"))
vw.q1[c(1:3, nrow(vw.q1)), ]
##          date     AMZN      MSFT      AAPL     TSLA
## 1  2016-12-30       NA        NA        NA       NA
## 2  2017-01-03 1.005068 1.0070809 1.0028492 1.015443
## 3  2017-01-04 1.004657 0.9955257 0.9988807 1.046085
## 63 2017-03-31 1.011639 1.0022828 0.9981242 1.001367

vw.q1[1, 2:5] <- 1
vw.q1$AMZN <- cumprod(vw.q1$AMZN) 
vw.q1$MSFT <- cumprod(vw.q1$MSFT)
vw.q1$AAPL <- cumprod(vw.q1$AAPL)
vw.q1$TSLA <- cumprod(vw.q1$TSLA)
vw.q1[c(1:3, nrow(vw.q1)), ]
##          date     AMZN     MSFT     AAPL     TSLA
## 1  2016-12-30 1.000000 1.000000 1.000000 1.000000
## 2  2017-01-03 1.005068 1.007081 1.002849 1.015443
## 3  2017-01-04 1.009748 1.002575 1.001727 1.062240
## 63 2017-03-31 1.182258 1.066290 1.245751 1.302354


vw.q1$AMZN.idx <- vw.q1$AMZN * q1.vw.wgt$AMZN.wgt #Apply the Q-end weights; note 
# that q1.vw.wgt$AMZN.wgt is a scalar
vw.q1$MSFT.idx <- vw.q1$MSFT * q1.vw.wgt$MSFT.wgt
vw.q1$AAPL.idx <- vw.q1$AAPL * q1.vw.wgt$AAPL.wgt
vw.q1$TSLA.idx <- vw.q1$TSLA * q1.vw.wgt$TSLA.wgt
vw.q1[c(1:3, nrow(vw.q1)), ]
##          date     AMZN     MSFT     AAPL     TSLA  AMZN.idx  MSFT.idx
## 1  2016-12-30 1.000000 1.000000 1.000000 1.000000 0.4096464 0.5501175
## 2  2017-01-03 1.005068 1.007081 1.002849 1.015443 0.4117223 0.5540129
## 3  2017-01-04 1.009748 1.002575 1.001727 1.062240 0.4136397 0.5515340
## 63 2017-03-31 1.182258 1.066290 1.245751 1.302354 0.4843078 0.5865851
##        AAPL.idx   TSLA.idx
## 1  0.0006971015 0.03953898
## 2  0.0006990877 0.04014958
## 3  0.0006983052 0.04199988
## 63 0.0008684147 0.05149374
#idx = daily gross returns * quarterly weight
#weight is based on market capitalization
#So larger firms would have a greater influence on portfolio returns

q1.vw.val <- data.frame(rowSums(vw.q1[, 6:9])) #Calculate the daily portfolio values
q1.vw.val[c(1:3, nrow(q1.vw.val)), ]
## [1] 1.000000 1.006584 1.007872 1.123255
names(q1.vw.val) <- paste("port.val")
q1.vw.val$date <- vw.q1$date
q1.vw.val[c(1:3, nrow(q1.vw.val)), ]
##    port.val       date
## 1  1.000000 2016-12-30
## 2  1.006584 2017-01-03
## 3  1.007872 2017-01-04
## 63 1.123255 2017-03-31

q2.vw.inv <- q1.vw.val[nrow(q1.vw.val), 1]
q2.vw.inv
## [1] 1.123255

Step 8: Calculate VW Portfolio Values for 2Q 2013

vw.q2 <- subset(vwport,
                vwport$date >= "2017-04-01" &
                vwport$date <= "2017-06-30")
vw.q2[c(1:3, nrow(vw.q2)), ]
##           date AMZN.Close MSFT.Close AAPL.Close TSLA.Close  AMZN.ret
## 64  2017-04-03     891.51      65.55     143.70     298.52 1.0056061
## 65  2017-04-04     906.83      65.73     144.77     303.70 1.0171843
## 66  2017-04-05     909.28      65.56     144.02     295.00 1.0027017
## 126 2017-06-30     968.00      68.93     144.02     361.61 0.9918744
##      MSFT.ret  AAPL.ret  TSLA.ret
## 64  0.9952930 1.0002784 1.0726554
## 65  1.0027460 1.0074461 1.0173523
## 66  0.9974135 0.9948194 0.9713533
## 126 1.0064242 1.0023665 1.0023839

vw.q2 <- vw.q2[, c(1, 6:9)]
vw.q2[c(1:3, nrow(vw.q2)), ]
##           date  AMZN.ret  MSFT.ret  AAPL.ret  TSLA.ret
## 64  2017-04-03 1.0056061 0.9952930 1.0002784 1.0726554
## 65  2017-04-04 1.0171843 1.0027460 1.0074461 1.0173523
## 66  2017-04-05 1.0027017 0.9974135 0.9948194 0.9713533
## 126 2017-06-30 0.9918744 1.0064242 1.0023665 1.0023839

names(vw.q2)[2:5] <- paste(c("AMZN", "MSFT", "AAPL", "TSLA"))
vw.q2[c(1:3, nrow(vw.q2)), ]
##           date      AMZN      MSFT      AAPL      TSLA
## 64  2017-04-03 1.0056061 0.9952930 1.0002784 1.0726554
## 65  2017-04-04 1.0171843 1.0027460 1.0074461 1.0173523
## 66  2017-04-05 1.0027017 0.9974135 0.9948194 0.9713533
## 126 2017-06-30 0.9918744 1.0064242 1.0023665 1.0023839

#vw.q2[1, 2:5] <- 1 #difference from Q1
vw.q2$AMZN <- cumprod(vw.q2$AMZN)
vw.q2$MSFT <- cumprod(vw.q2$MSFT)
vw.q2$AAPL <- cumprod(vw.q2$AAPL)
vw.q2$TSLA <- cumprod(vw.q2$TSLA)
vw.q2[c(1:3, nrow(vw.q2)), ]
##           date     AMZN      MSFT     AAPL     TSLA
## 64  2017-04-03 1.005606 0.9952930 1.000278 1.072655
## 65  2017-04-04 1.022887 0.9980261 1.007727 1.091269
## 66  2017-04-05 1.025650 0.9954448 1.002506 1.060007
## 126 2017-06-30 1.091885 1.0526131 1.006644 1.299353

vw.q2$AMZN.ind <- (q2.vw.inv * q2.vw.wgt$AMZN.wgt) * vw.q2$AMZN #Apply weight
vw.q2$MSFT.ind <- (q2.vw.inv * q2.vw.wgt$MSFT.wgt) * vw.q2$MSFT
vw.q2$AAPL.ind <- (q2.vw.inv * q2.vw.wgt$AAPL.wgt) * vw.q2$AAPL
vw.q2$TSLA.ind <- (q2.vw.inv * q2.vw.wgt$TSLA.wgt) * vw.q2$TSLA
vw.q2[c(1:3, nrow(vw.q2)), ]
##           date     AMZN      MSFT     AAPL     TSLA  AMZN.ind  MSFT.ind
## 64  2017-04-03 1.005606 0.9952930 1.000278 1.072655 0.4890146 0.5809335
## 65  2017-04-04 1.022887 0.9980261 1.007727 1.091269 0.4974180 0.5825288
## 66  2017-04-05 1.025650 0.9954448 1.002506 1.060007 0.4987619 0.5810221
## 126 2017-06-30 1.091885 1.0526131 1.006644 1.299353 0.5309712 0.6143901
##         AAPL.ind   TSLA.ind
## 64  0.0008584465 0.05623660
## 65  0.0008648385 0.05721244
## 66  0.0008603581 0.05557349
## 126 0.0008639093 0.06812179

q2.vw.val <- data.frame(rowSums(vw.q2[, 6:9]))
q2.vw.val[c(1:3, nrow(q2.vw.val)), ]
## [1] 1.127043 1.138024 1.136218 1.214347

names(q2.vw.val) <- paste("port.val")
q2.vw.val[c(1:3, nrow(q2.vw.val)), ]
## [1] 1.127043 1.138024 1.136218 1.214347

q2.vw.val$date <- vw.q2$date
q2.vw.val[c(1:3, nrow(q2.vw.val)), ]
##     port.val       date
## 64  1.127043 2017-04-03
## 65  1.138024 2017-04-04
## 66  1.136218 2017-04-05
## 126 1.214347 2017-06-30

#$1.104 at the end of Q1 and $1.056 by the end of Q2
#it doesn't mean that the portfolio grew 5.6% during Q2 but 5.6% during Q1-Q2
#b/c it's a cumulative measure

Step 11: Combine Quarterly VW Portfolio Values into One Data Object

vw.portval <- rbind(q1.vw.val, q2.vw.val)
vw.portval[c(1:3, nrow(vw.portval)), ]
##     port.val       date
## 1   1.000000 2016-12-30
## 2   1.006584 2017-01-03
## 3   1.007872 2017-01-04
## 126 1.214347 2017-06-30

3.3.3 Normalized EW and VW Portfolio Price Chart

Compare the performance of EW and VW portfolio from 12/30/2016 to 12/31/2017

Step 1: Combine the Data

port.val <- merge(vw.portval, ew.portval, by = "date")
port.val[c(1:3, nrow(port.val)), ]
##           date port.val.x port.val.y
## 1   2016-12-30   1.000000   1.000000
## 2   2017-01-03   1.006584   1.007610
## 3   2017-01-04   1.007872   1.019072
## 126 2017-06-30   1.214347   1.334218

Step 2: Rename the Variables

names(port.val)[2:3] <- paste(c("VW.cum", "EW.cum"))
port.val[c(1:3, nrow(port.val)), ]
##           date   VW.cum   EW.cum
## 1   2016-12-30 1.000000 1.000000
## 2   2017-01-03 1.006584 1.007610
## 3   2017-01-04 1.007872 1.019072
## 126 2017-06-30 1.214347 1.334218

Step 3: Plot the Data

par(mfrow = c(1, 1))
y.range <- range(port.val[, 2:3])
y.range
## [1] 1.000000 1.394362
plot(x = port.val$date,
     y = port.val$EW.cum,
     xlab = "Date",
     ylab = "Value of Investment",
     ylim = y.range,
     type = "l",
     lty = 1,
     main = "Value of R1 Investment in Equal-Weighted and
          Value-Weighted Portfolio of AMZN, MSFT, AAPL, and TSLA
          December 30, 2016 - June 30, 2017")
lines(x = port.val$date,
      y = port.val$VW.cum, 
      lty = 2)
abline(h = 1, lty = 1)
legend("topleft",
       c("Equal-Weighted Portfolio", "Value-Weighted Portfolio"), #typo in the textbook
       lty = c(1, 2))

1. If you invested 100 at the beginning of the period your gross return would be $133

2 If you invested 100 at the beginning of the period your gross net income would be $21

3. Tesla performed the best

4. Equal weighted stocks did best