Package stockPortfolio [629536]

Package ‘stockPortfolio’
February 20, 2015
Type Package
Title Build stock models and analyze stock portfolios.
Version 1.2
Date 2012-03-14
Author David Diez and Nicolas Christou
Maintainer David Diez <[anonimizat]>
Description Download stock data, build single index, constant
correlation, and multigroup models, and estimate optimal stock
portfolios. Plotting functions for the portfolio possibilities
curve and portfolio cloud are included. A function to test a
portfolio on a data set is also provided.
License GPL (>= 2)
LazyLoad yes
Depends stats, graphics, grDevices, utils
Repository CRAN
Date/Publication 2012-03-14 16:03:05
NeedsCompilation no
Rtopics documented:
stockPortfolio-package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
adjustBeta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
getCorr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
getReturns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
optimalPort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
portCloud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
portPossCurve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
portReturn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
stock04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
stock94 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
stock94Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
stock99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1

2 stockPortfolio-package
stockModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
testPort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Index 23
stockPortfolio-package
Build and manage stock models and portfolios
Description
The package stockPortfolio is a quantitative approach to portfolio allocation among stocks. The
package includes functions to download historical data from Yahoo Finance, build models, estimate
optimal portfolios, and test portfolios. A large range of graphical features have been included for
visual understanding.
Details
Package: stockPortfolio
Type: Package
Version: 1.2
Date: 2012-03-14
License: GPL (>= 2)
LazyLoad: yes
A common starting point in the package is with the getReturns function, which can be used to
obtain stock data using an internet connection. Using an object of class "stockReturns" from the
getReturns function, one can build a stock model using the stockModel function. There are four
model options in stockModel : no model where a portfolio is selected based on empirical returns,
variances, and covariances among the stocks, the single index model, constant correlation model,
and the multigroup model. After a stock model has been built, the user can obtain an estimate
of the optimal portfolio allocation among those stocks using optimalPort . Additionally, one can
test out models and portfolios on data sets that are either supplied by the user or are output from
getReturns .
While most objects can be plotted, there are two specialty plotting functions: portPossCurve and
portCloud . The function portPossCurve plots the portfolio possibilities curve based on a model,
andportCloud plots a cloud of possible portfolios based on a model.
Three data sets and one data "key" have been included as a sample data set: stock94 ,stock99 ,
stock04 ,stock94Info .
Author(s)
David Diez and Nicolas Christou wrote the package functions.
Maintainer: David Diez <david.m.diez@gmail.com>

stockPortfolio-package 3
References
Blume, Marshall E. "Portfolio Theory: A Step Toward Its Practical Application," Journal of Busi-
ness, 43, No. 2 (April 1970), pp. 152-173.
Markowitz, Harry. "Portfolio Selection Efficient Diversification of Investments." New York: John
Wiley and Sons, 1959.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection," Journal of Finance, XI, No. 5 (Dec. 1976), pp. 1341-1357.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Rules for Optimal Portfolio
Selection: The Multi Group Case," Journal of Financial and Quantitative Analysis, XII, No. 3
(Sept. 1977), pp. 329-345.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection: Tracing Out the Efficient Frontier," Journal of Finance, XIII, No. 1 (March 1978), pp.
296-302.
Elton, E.J., Gruber, M.J., Brown, S.J., and Goetzmann, W.N. "Modern Portfolio Theory and Invest-
ment Analysis" (6th Edition). John Wiley and Sons, 2003.
Examples
#===> two examples of downloading data <===#
## Not run: grEx1 <- getReturns(c( /quotesingleVarC/quotesingleVar,/quotesingleVarBAC/quotesingleVar), start= /quotesingleVar2004-01-01 /quotesingleVar, end= /quotesingleVar2008-12-31 /quotesingleVar)
## Not run: grEx2 <- getReturns(c( /quotesingleVarKEY/quotesingleVar,/quotesingleVarWFC/quotesingleVar,/quotesingleVarJPM/quotesingleVar,/quotesingleVarAMR/quotesingleVar,/quotesingleVarBIIB /quotesingleVar,/quotesingleVarAMGN /quotesingleVar))
#===> build four models <===#
data(stock99)
data(stock94Info)
non <- stockModel(stock99, drop=25, model= /quotesingleVarnone /quotesingleVar, industry=stock94Info$industry)
sim <- stockModel(stock99, model= /quotesingleVarSIM/quotesingleVar, industry=stock94Info$industry, index=25)
ccm <- stockModel(stock99, drop=25, model= /quotesingleVarCCM/quotesingleVar, industry=stock94Info$industry)
mgm <- stockModel(stock99, drop=25, model= /quotesingleVarMGM/quotesingleVar, industry=stock94Info$industry)
#===> build optimal portfolios <===#
opNon <- optimalPort(non)
opSim <- optimalPort(sim)
opCcm <- optimalPort(ccm)
opMgm <- optimalPort(mgm)
#===> test portfolios on 2004-9 <===#
data(stock04)
tpNon <- testPort(stock04, opNon)
tpSim <- testPort(stock04, opSim)
tpCcm <- testPort(stock04, opCcm)
tpMgm <- testPort(stock04, opMgm)
#===> compare performances <===#
plot(tpNon)
lines(tpSim, col=2, lty=2)
lines(tpCcm, col=3, lty=3)
lines(tpMgm, col=4, lty=4)
legend( /quotesingleVartopleft /quotesingleVar, col=1:4, lty=1:4, legend=c( /quotesingleVarnone /quotesingleVar,/quotesingleVarSIM/quotesingleVar,/quotesingleVarCCM/quotesingleVar,/quotesingleVarMGM/quotesingleVar))

4 adjustBeta
adjustBeta Adjust the beta parameters from a single index model
Description
Given a stockModel object that is based on the single index model, the beta parameters may be
adjusted using either the Blume or Vasicek technique. This function outputs a new object of class
"stockModel" based on the single index model.
Usage
adjustBeta(model, model2 = NULL, method = c("Blume", "Vasicek"))
Arguments
model An object of class "stockModel" that is based on the single index model. If
using Blume’s method, then this model should be for the first period.
model2 An object of class "stockModel" that is based on the single index model. If
using Blume’s method, then this model should be for the second period. If using
Vasicek’s method, then this model is ignored.
method The single index model adjustment method. The options are "Blume" (default)
or"Vasicek" . Setting it to any character string other than "B","b","Blume" ,
"blume" , or"1"will result in using the Vasicek method.
Details
The single index model results in a vector of parameter estimates, which is typically labeled using
the Greek letter beta. Both the Blume and Vasicek methods adjust the beta parameter vector. Va-
sicek’s method regresses all of the elements of beta towards the mean of those elements; the amount
of this correction is based both on the variability of the elements of beta and also on the estimated
standard error of each element of beta. Blume’s method takes beta estimates from two time periods
and creates a regression equation: beta2 = b0 + b1*beta1. Blume’s method uses this regression
equation to estimate beta for the time following the second period.
Value
adjustBeta returns an object of class "stockModel" .
Author(s)
David Diez
References
Blume, Marshall E. "Portfolio Theory: A Step Toward Its Practical Application," Journal of Busi-
ness, 43, No. 2 (April 1970), pp. 152-173.

getCorr 5
See Also
getReturns ,stockModel ,optimalPort
Examples
#===> build two single index models <===#
data(stock94)
data(stock99)
data(stock94Info)
sim1 <- stockModel(stock94, model= /quotesingleVarSIM/quotesingleVar,
industry=stock94Info$industry, index=25)
sim2 <- stockModel(stock99, model= /quotesingleVarSIM/quotesingleVar,
industry=stock94Info$industry, index=25)
#===> adjust the betas <===#
# the output is a new stock model
simBlu <- adjustBeta(sim1, sim2)
simVas <- adjustBeta(sim2, method= /quotesingleVarVasicek /quotesingleVar)
#===> build optimal portfolios <===#
opSim <- optimalPort(sim2)
opBlu <- optimalPort(simBlu)
opVas <- optimalPort(simVas)
#===> test portfolios on 2004-9 <===#
data(stock04)
tpSim <- testPort(stock04, opSim)
tpBlu <- testPort(stock04, opBlu)
tpVas <- testPort(stock04, opVas)
#===> compare performances <===#
plot(tpSim, ylim=c(1,2.2))
lines(tpBlu, col=2, lty=2)
lines(tpVas, col=3, lty=3)
legend( /quotesingleVartopleft /quotesingleVar, col=1:3, lty=1:3, legend=c( /quotesingleVarnone /quotesingleVar,/quotesingleVarBlume /quotesingleVar,/quotesingleVarVasicek /quotesingleVar))
getCorr Average correlation
Description
Determine the average correlation or average correlation by industry of a variance-covariance ma-
trix.
Usage
getCorr(V, industry = NULL)

6 getReturns
Arguments
V Variance-covariance matrix.
industry A vector specifying the industry of the stocks in their order given in the columns
(and rows) of V. This argument is optional.
Value
Ifindustry is not provided, then the average correlation in Vin the matrix is returned but ignoring
the diagonal. If industry is provided, then the output is a matrix with dimension k-by-k, where k
is the number of unique values in industry .
Author(s)
David Diez
See Also
stockModel
Examples
#===> the covariance matrix of stock94 <===#
data(stock94)
data(stock94Info)
V <- cov(stock94)
#===> the average correlation <===#
getCorr(V)
getCorr(V, industry=stock94Info$industry)
getReturns Obtain stock data from Yahoo Finance
Description
Download a collection of stock data from Yahoo Finance.
Usage
getReturns(ticker, freq = c("month", "week", "day"),
get = c("overlapOnly", "all"), start = "1970-01-01", end = NULL)

getReturns 7
Arguments
ticker A character vector where each element is a ticker.
freq The frequency of the stock data to be downloaded. Default is "month" for 12
observations per year and other options are "week" and"day" .
get The default, "overlapOnly" , will return the stock returns for which all stocks
had data and drop any dates with NA; if it is monthly data, minor corrections are
made when appropriate. The "all" option yields all stock returns regardless
of whether data for all stocks is available; stock data obtained under the "all"
option may not work in the other functions in this package if NAvalues are
present.
start Start date in the format "YYYY-MM-DD" .
end End date in the format "YYYY-MM-DD" . If using freq="month" (the default) or
freq="week" , the DDshould be specified as the last day of the month or week,
respectively.
Value
getReturns outputs an object of class "stockReturns" , which is a list of the following:
R Stock returns, where the first row is the most recent and the last row is the oldest.
ticker The tickers of the stocks.
period How frequently stock returns are included in the data.
start The oldest date for which stock returns are included.
end The most recent date for which stock returns are included.
full A list, where each item is a data frame containing information from the CSV file
downloaded from Yahoo Finance.
Author(s)
David Diez and Nicolas Christou
See Also
stockModel ,optimalPort ,testPort ,portReturn
Examples
#===> Citi and Bank of America, 2004-2008 <===#
# cBac <- getReturns(c( /quotesingleVarC/quotesingleVar,/quotesingleVarBAC/quotesingleVar), start= /quotesingleVar2004-01-01 /quotesingleVar, end= /quotesingleVar2008-12-31 /quotesingleVar)
# print(cBac)
# summary(cBac)
# plot(cBac)
# lines(cBac, lwd=2)
# pairs(cBac)

8 optimalPort
optimalPort Estimate the optimal portfolio
Description
optimalPort estimates the optimal portfolio based on a stock model and data set.
Usage
optimalPort(model, Rf = NULL, shortSell = NULL, eps = 10^(-4))
Arguments
model An object of class "stockModel" .
Rf An optional argument to update the risk free rate.
shortSell An optional argument to update short-selling.
eps An error term to be used in evaluating whether the risk-free rate is acceptable.
This argument should not be adjusted except by advanced users.
Details
When the function returns an error regarding the validity of Rf, the risk free rate of return, this is
not a bug. That error message means the Rfis too large; it is larger than the expected return of the
vertex of the portfolio possibilities curve (the left-most point on this curve). When this occurs, no
tangent line can be created along the efficient frontier. The implication is that a lower Rf should be
specified to identify a portfolio along the efficient frontier of the portfolio possibilities curve.
This Rf issue has happened relatively frequently with stocks in the last few years. So many stocks
are down, which sometimes results in a minimum risk portfolios with an expected return that is
negative.
Value
optimalPort outputs an object of class "optimalPortfolio" , which is a list of
model An object of class "stockModel" .
X The allocation of the optimal portfolio.
R The estimated return associated with allocation X.
risk The estimated risk associated with allocation X.
Author(s)
David Diez and Nicolas Christou

optimalPort 9
References
Markowitz, Harry. "Portfolio Selection Efficient Diversification of Investments." New York: John
Wiley and Sons, 1959.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection," Journal of Finance, XI, No. 5 (Dec. 1976), pp. 1341-1357.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Rules for Optimal Portfolio
Selection: The Multi Group Case," Journal of Financial and Quantitative Analysis, XII, No. 3
(Sept. 1977), pp. 329-345.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection: Tracing Out the Efficient Frontier," Journal of Finance, XIII, No. 1 (March 1978), pp.
296-302.
See Also
getReturns ,stockModel ,testPort
Examples
#===> obtain data <===#
data(stock99)
data(stock94Info)
mgm <- stockModel(stock99, drop=25, model= /quotesingleVarMGM/quotesingleVar, industry=stock94Info$industry)
#===> build optimal portfolios <===#
opMgm1 <- optimalPort(mgm)
opMgm2 <- optimalPort(mgm, Rf=0.004)
print(opMgm1)
summary(opMgm1)
#===> plot the optimal porfolios <===#
par(mfrow=c(1,2))
# these plots provide a "head coloring" of
# the allocation by optimalPort
plot(opMgm1)
plot(opMgm2)
#===> additional plotting 1 <===#
par(mfrow=c(1,1))
plot(opMgm1, addNames=TRUE)
#===> additional plotting 2 <===#
plot(opMgm1, optPortOnly=TRUE, colOP=2, pchOP=2)
points(opMgm2, colOP=2, pchOP=4)
#=====> Watch out – choosing Rf too large causes errors <=====#
data(stock99)
data(stock94Info)
non <- stockModel(stock99, drop=25, model= /quotesingleVarnone /quotesingleVar,
industry=stock94Info$industry)
portPossCurve(non)

10 portCloud
opTemp <- optimalPort(non, Rf=-10^5)
points(opTemp)
## Error if Rf >= vertex (y value)
# optimalPort(non, 0.02)
# optimalPort(non, opTemp$R)
# optimalPort(non, opTemp$R+0.01)
# optimalPort(non, opTemp$R-0.01)
## May give error if Rf too close to vertex
# optimalPort(non, opTemp$R-0.0001)
portCloud Plot a portfolio cloud
Description
Given a model with short-selling permitted, portCloud plots a cloud of possible portfolios.
Usage
portCloud(model, riskRange = 2, detail = 25, N = 3000, add = TRUE,
col = c("#55550044"), pch = 20, subSamp = 1000, xlim = "default",
ylim = "default", xlab = "Risk", ylab = "Return", …)
Arguments
model An object of class "stockModel" .
riskRange A factor to specify how large you would like the portfolio cloud to be. If Xis
the portfolio with minimum risk, then the portfolio cloud will look aesthetically
best to approximately risk of riskRange*X .
detail A parameter that adjusts the appearance of the portfolio cloud. The default value
is often adequate.
N A parameter for the number of portfolios to consider.
add IfTRUE , then the points are added to the plot. If FALSE , a new plot is created.
col Color of the portfolios in the plot.
pch Plotting character of the portfolios.
subSamp The maximum number of portfolios to plot.
xlim Limits for the x axis. Only applied if add=FALSE .
ylim Limits for the y axis. Only applied if add=FALSE .
xlab Label for the x axis. Only applied if add=FALSE .
ylab Label for the y axis. Only applied if add=FALSE .
… Ifadd=FALSE , additional arguments for plot . If add=TRUE , additional argu-
ments for points .

portPossCurve 11
Details
Which portfolios are actually plotted is dependent on the portfolio possibilities curve. A number
of points along the curve, specified by detail and the stocks themselves are used to produce a
relatively uniform looking portfolio cloud.
Value
A list of the following items:
ports The portfolios plotted.
R The estimated return associated with each row of ports .
risk The estimated risk associated with each row of ports .
Author(s)
David Diez and Nicolas Christou
See Also
stockModel ,portPossCurve
Examples
data(stock94)
sm <- stockModel(stock94, model= /quotesingleVarSIM/quotesingleVar, index=25)
portCloud(sm, add=FALSE)
portPossCurve(sm, 2.5, add=TRUE)
portPossCurve Plot the portfolio possibilities curve
Description
Plot the portfolio possibilities curve or the efficient frontier for models that permit short-selling.
Usage
portPossCurve(model, riskRange = 2, detail = 100, effFrontier = FALSE,
add = FALSE, type = "l", xlab = "Risk", ylab = "Expected Return",
doNotPlot = FALSE, …)

12 portPossCurve
Arguments
model An object of class "stockModel" .
riskRange A parameter to specify how much of the portfolio possibilities curve to plot.
IfXis the portfolio with minimum risk without respect to the risk free rate,
then the portfolio possibilities curve will be shown up to approximately the risk
riskRange*X .
detail The number of points to include on the portfolio possibilities curve. A small
number will result a curve that is evidently made up of lines while a large number
will provide more detail but takes more memory. The default value is generally
adequate.
effFrontier IfTRUE , only the efficient frontier is drawn.
add IfTRUE , the curve is added to a plot. Otherwise a new plot is created.
type Plotting method. "p"for points, "l"for lines, "b"for both lines and points, and
"n"to produce no points or lines.
xlab Label for the x axis. Only applied if add=FALSE .
ylab Label for the y axis. Only applied if add=FALSE .
doNotPlot IfFALSE , nothing is plotted. This option may be useful if the points along the
curve are of interest and only the values returned by portPossCurve are of
interest.
… Ifadd=FALSE , additional arguments for plot .Ifadd=TRUE , additional arguments
forpoints .
Details
If the curve is not smooth, first try decreasing the riskRange . If this is unsuccessful in producing
a plot to the detail desired, increase the detail . Generally it is advisable to attempt to adjust the
riskRange before adjusting detail .
Value
portPossCurve returns a list of the following items:
R The returns of points along the curve.
risk The risk of points along the curve.
ports The portfolios corresponding to Randrisk .
Author(s)
David Diez
See Also
stockModel ,portCloud

portReturn 13
Examples
data(stock94)
sm <- stockModel(stock94, model= /quotesingleVarSIM/quotesingleVar, index=25)
portPossCurve(sm, 2)
portCloud(sm, 2.5)
portReturn Estimate return and risk of a portfolio
Description
Given a portfolio allocation Xand a model, identify the estimated return and risk associated with X.
Usage
portReturn(model, X)
Arguments
model An object of class "stockModel" .
X The portfolio allocation.
Value
portReturn returns a list of the following items:
R The estimated return.
V The estimated risk squared.
X The allocation, which is the second argument.
ticker The tickers from the model.
model An object of class "stockModel" , which is the same model provided to the
function.
Author(s)
David Diez
See Also
stockModel

14 stock04
Examples
#===> basics <===#
data(stock94)
sm <- stockModel(stock94, model= /quotesingleVarSIM/quotesingleVar, index=25)
op <- optimalPort(sm)
prOp <- portReturn(sm, op$X)
prUn <- portReturn(sm, rep(1, 24)/24)
print(prOp)
summary(prOp)
summary(prUn)
#===> plotting a "portReturn" object <===#
par(mfrow=c(2,2))
plot(prOp) # provides a heat map of the allocation
plot(prUn) # a boring heat map of allocation
plot(prOp, col=2:5) # many random colors
plot(prUn, col=1) # all black
stock04 Data for 24 stocks and 1 index, 2004-9
Description
Sixty monthly stock observations from 2004-10-01 to2009-09-01 for 24 stocks in six industries.
There is also a 25th column for an index, the S&P500.
Usage
data(stock04)
Format
The format is numerical with 60 rows and 25 columns. The column names provide the tickers, and
row names describe the dates.
Details
Seestock94Info for a breakdown of the stocks by industry.
Source
Yahoo Finance.
See Also
stock94Info ,stock94 ,stock99 ,stockModel

stock94 15
Examples
data(stock04)
data(stock94Info)
sm <- stockModel(stock04, model= /quotesingleVarSIM/quotesingleVar, index=25,
industry=stock94Info$industry)
stock94 Data for 24 stocks and 1 index, 1994-9
Description
Sixty monthly stock observations from 1994-10-03 to1999-09-01 for 24 stocks in six industries.
There is also a 25th column for an index, the S&P500.
Usage
data(stock94)
Format
The format is numerical with 60 rows and 25 columns. The column names provide the tickers, and
row names describe the dates.
Details
Seestock94Info for a breakdown of the stocks by industry.
Source
Yahoo Finance.
See Also
stock94Info ,stock99 ,stock04 ,stockModel
Examples
data(stock94)
data(stock94Info)
sm <- stockModel(stock94, model= /quotesingleVarSIM/quotesingleVar, index=25,
industry=stock94Info$industry)

16 stock99
stock94Info Ticker and industry information
Description
A data frame showing the industries of each of the stocks given in stock94 ,stock99 , and stock04 .
Usage
data(stock94Info)
Format
A data frame with 25 observations with two columns: ticker and industry.
Source
Yahoo Finance.
See Also
stock94 ,stock99 ,stock04
Examples
data(stock94Info)
data(stock04)
sm <- stockModel(stock04, model= /quotesingleVarSIM/quotesingleVar, index=25,
industry=stock94Info$industry)
stock99 Data for 24 stocks and 1 index, 1999-2004
Description
Sixty monthly stock observations from 1999-10-01 to2004-09-01 for 24 stocks in six industries.
There is also a 25th column for an index, the S&P500.
Usage
data(stock99)
Format
The format is numerical with 60 rows and 25 columns. The column names provide the tickers, and
row names describe the dates.

stockModel 17
Details
Seestock94Info for a breakdown of the stocks by industry.
Source
Yahoo Finance.
See Also
stock94Info ,stock94 ,stock04 ,stockModel
Examples
data(stock99)
data(stock94Info)
sm <- stockModel(stock99, model= /quotesingleVarSIM/quotesingleVar, index=25,
industry=stock94Info$industry)
stockModel Create a stock model
Description
Input an object of class "stockReturns" and select a model. Available choices are "none" ,"SIM"
(single index model), "CCM" (constant correlation model), and "MGM" (multigroup model).
Usage
stockModel(stockReturns, drop = NULL, Rf = 0, shortSelling = c("y", "n"),
model = c("none", "SIM", "CCM", "MGM"), industry = NULL, index = NULL,
get = c("overlapOnly", "all"), freq = c("month", "week", "day"),
start = "1970-01-01", end = NULL, recentLast = FALSE,
rawStockPrices = FALSE)
Arguments
stockReturns An object of class "stockReturns" . Additionally, a character vector of tickers
can also be used here, in which case also see argument freq ,get,start , and
end. Additionally, an object of class "stockModel" can also be input here,
which will permit model adjustments, including switching the model altogether.
Finally, stock data can also be submitted here as a matrix; the column names
should be the ticker names and the row names should be the dates of the returns,
YYYY-MM-DD . Additionally, for outside data sets where the oldest stock return is
in row 1 (and not the last row), see argument recentLast .
drop Declare any stocks to be dropped. For instance, if the model "none" ,"CCM" , or
"MGM" is used, stock indices might be dropped.

18 stockModel
Rf The risk free rate of return, which must be standardized for the period (e.g. a
2% yearly rate for monthly data would imply Rf=0.02/12 , or 2% with daily
data would imply Rf=0.02/250 if there are 250 trading days per year.). The
default value is 0.
shortSelling Either "yes" (default) or "no" . Some models, "none" and"MGM" , will permit
short-selling regardless of this selection.
model Either no model ( "none" , the default), the single index model ( "SIM" ), constant
correlation model ( "CCM" ), or the multigroup model ( "MGM" ).
industry A character or factor vector containing the industries corresponding to stockRe-
turns. This argument is optional except when model="MGM" , however, it may be
included in any model for slightly enhanced graphics.
index When using model="SIM" , the index is the column number indicating the stock
index. Warning if using drop and also specifying the index: The value of index
should correspond to the column number AFTER dropping columns. See De-
tails below.
get "overlapOnly" (default) obtains stock returns for which all stocks had data and
drops any dates with NA."all" yields all stock returns regardless of whether
data for all stocks is available. This argument is ignored unless stockReturns
is a vector of tickers.
freq The time period between each stock return. Default is "month" and other options
are"week" and"day" . This argument is ignored unless stockReturns is a
vector of tickers.
start Start date in the format "YYYY-MM-DD" . This argument is ignored unless stockReturns
is a vector of tickers.
end End date in the format "YYYY-MM-DD" . This argument is ignored unless stockReturns
is a vector of tickers.
recentLast Set this argument to TRUE if (1) you are using your own data that was not ob-
tained by getReturns and (2) your matrix of returns runs from oldest returns
(row 1) to most recent returns (last row).
rawStockPrices Set to TRUE if (1) you are using your own data that was not obtained by getReturns
and (2) your matrix is of stock prices and not of stock returns.
Details
The multigroup model is the least known of the models presented here. It is similar to the con-
stant correlation model, except that instead of assuming a constant correlation across all stocks,
correlations are only dependent on the industry of a stock.
If stocks are dropped using the argument drop , then index must correspond to the position of the
index AFTER those stocks are dropped. For instance, if there are seven stocks, the index is in
position six, and the fourth stock is dropped, then we should use index=5 .
Value
stockModel outputs an object of class "stockModel" , which is a list of the following items, many
of which might be NA:

stockModel 19
model The model selected.
ticker A vector of the tickers of the stocks included in the model.
index The index number, if provided by the user.
theIndex Ticker of the index.
industry Industries associated with the stocks.
returns Return data used to build the model.
marketReturns Return data of the index.
n Number of observations per stock.
start The oldest date for which stock returns are included.
end The most recent date for which stock returns are included.
period How frequently stock returns are included in the data.
R Average returns of the stocks.
COV Variance-covariance matrix of the stock returns.
sigma Standard deviation of the returns of the stocks (square root of the diagonal of
COV).
shorts Whether short sales are allowed.
Rf Risk free return rate.
alpha Vector of intercepts in the linear model for the single index model.
vAlpha The square of the standard errors of alpha .
beta Vector of coefficients in the linear model for the single index model.
vBeta The square of the standard errors of beta .
betaAdj Whether the model was adjusted via adjustBeta .
MSE Variance of error term associated with single index model for each stock.
RM Mean market return.
VM Variance of the market return.
rho Mean correlation or, if using model="MGM" , the matrix of averaged correlations.
SeegetCorr .
Author(s)
David Diez and Nicolas Christou
References
Markowitz, Harry. "Portfolio Selection Efficient Diversification of Investments." New York: John
Wiley and Sons, 1959.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection," Journal of Finance, XI, No. 5 (Dec. 1976), pp. 1341-1357.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Rules for Optimal Portfolio
Selection: The Multi Group Case," Journal of Financial and Quantitative Analysis, XII, No. 3
(Sept. 1977), pp. 329-345.
Elton, Edwin, J., Gruber, Martin, J., Padberg, Manfred, W. "Simple Criteria for Optimal Portfolio
Selection: Tracing Out the Efficient Frontier," Journal of Finance, XIII, No. 1 (March 1978), pp.
296-302.

20 testPort
See Also
getReturns ,adjustBeta ,optimalPort ,testPort
Examples
#===> build four models <===#
data(stock99)
data(stock94Info)
non <- stockModel(stock99, drop=25, model= /quotesingleVarnone /quotesingleVar, industry=stock94Info$industry)
sim <- stockModel(stock99, model= /quotesingleVarSIM/quotesingleVar, industry=stock94Info$industry, index=25)
ccm <- stockModel(stock99, drop=25, model= /quotesingleVarCCM/quotesingleVar, industry=stock94Info$industry)
mgm <- stockModel(stock99, drop=25, model= /quotesingleVarMGM/quotesingleVar, industry=stock94Info$industry)
#===> build optimal portfolios <===#
opNon <- optimalPort(non)
opSim <- optimalPort(sim)
opCcm <- optimalPort(ccm)
opMgm <- optimalPort(mgm)
#===> test portfolios on 2004-9 <===#
data(stock04)
tpNon <- testPort(stock04, opNon)
tpSim <- testPort(stock04, opSim)
tpCcm <- testPort(stock04, opCcm)
tpMgm <- testPort(stock04, opMgm)
#===> compare performances <===#
plot(tpNon)
lines(tpSim, col=2, lty=2)
lines(tpCcm, col=3, lty=3)
lines(tpMgm, col=4, lty=4)
legend( /quotesingleVartopleft /quotesingleVar, col=1:4, lty=1:4, legend=c( /quotesingleVarnone /quotesingleVar,/quotesingleVarSIM/quotesingleVar,/quotesingleVarCCM/quotesingleVar,/quotesingleVarMGM/quotesingleVar))
testPort Test a portfolio on a data set
Description
Test a portfolio allocation on a new data set. This function is useful for comparing portfolios under
different data scenarios.
Usage
testPort(theData, model = NULL, X = NULL, newestFirst = TRUE,
isReturns = NULL)

testPort 21
Arguments
theData The data set to be used. This may be an object of class "stockReturns" , a
vector of 1plus the returns on each stock, or a matrix of stock returns where
rows are ordered observations and columns represent individual stocks (see also
argument newestFirst ). The matrix may also be stock prices, in which case
see argument isReturns .
model An object of class "stockModel" or of class "optimalPortfolio" . The alloca-
tion will be set as the optimal portfolio’s allocation. To set a different allocation,
leave this argument as NULL and use argument X.
X The stock allocation of the portfolio, where element icorresponds to stock iin
argument theData . Ifmodel is given, this argument is ignored.
newestFirst If argument theData is a matrix of stock returns or stock prices, and the rows
run from oldest (row 1) to most recent (last row), set newestFirst=FALSE .
isReturns If argument theData is a matrix of stock prices and not stock returns, set this
argument as FALSE .
Details
When the argument Xis used or if theData is not from getReturns , provide column names to
theData that correspond with the names of the elements of X. IftheData is a vector of one plus
the returns of each stock, then this vector should have its element names corresponding to those
elements in X.
IftheData is an object of class "stockReturns" or is a matrix of returns or prices, then this will
allow the resulting object of class "testPort" to be plotted. See the examples for details.
Value
testPort outputs an object of class "testPort" , which consists of the following items:
X The allocation used.
sumRet Summary of the returns for each stock.
change The value of the portfolio if it started at 1.
returns Return data, if provided.
Author(s)
David Diez and Nicolas Christou
See Also
getReturns ,stockModel ,optimalPort ,portReturn

22 testPort
Examples
#===> build two single index models <===#
data(stock99)
data(stock94Info)
non <- stockModel(stock99, drop=25, model= /quotesingleVarnone /quotesingleVar, industry=stock94Info$industry)
sim <- stockModel(stock99, model= /quotesingleVarSIM/quotesingleVar, industry=stock94Info$industry, index=25)
ccm <- stockModel(stock99, drop=25, model= /quotesingleVarCCM/quotesingleVar, industry=stock94Info$industry)
mgm <- stockModel(stock99, drop=25, model= /quotesingleVarMGM/quotesingleVar, industry=stock94Info$industry)
#===> build optimal portfolios <===#
opNon <- optimalPort(non)
opSim <- optimalPort(sim)
opCcm <- optimalPort(ccm)
opMgm <- optimalPort(mgm)
#===> test portfolios on 2004-9 <===#
data(stock04)
tpEqu <- testPort(stock04[,-25], X=rep(1,24)/24)
tpNon <- testPort(stock04, opNon)
tpSim <- testPort(stock04, opSim)
tpCcm <- testPort(stock04, opCcm)
tpMgm <- testPort(stock04, opMgm)
print(tpEqu)
summary(tpEqu)
#===> compare performances <===#
plot(tpEqu, ylim=c(1, 3))
lines(tpNon, col=2, lty=2)
lines(tpSim, col=3, lty=3)
lines(tpCcm, col=4, lty=4)
# a sample of how to use points on an object of
# class "testPort", however, its use makes the
# plot somewhat ugly
points(tpMgm, col=5, lty=5, type= /quotesingleVarb/quotesingleVar)
legend( /quotesingleVartopleft /quotesingleVar, col=1:5, lty=1:5, legend=c( /quotesingleVarequal all. /quotesingleVar,/quotesingleVarnone /quotesingleVar,/quotesingleVarSIM/quotesingleVar,/quotesingleVarCCM/quotesingleVar,/quotesingleVarMGM/quotesingleVar), pch=c(NA, NA, NA, NA, 1))

Index
Topic datasets
stock04 , 14
stock94 , 15
stock94Info , 16
stock99 , 16
Topic package
stockPortfolio-package , 2
adjustBeta , 4,19, 20
getCorr , 5,19
getReturns ,2,5, 6,9,18,20, 21
lines.stockReturns (getReturns ), 6
lines.testPort (testPort ), 20
optimalPort ,2,5,7, 8,20, 21
pairs.stockReturns (getReturns ), 6
plot ,12
plot.optimalPortfolio (optimalPort ), 8
plot.portReturn (portReturn ), 13
plot.stockModel (stockModel ), 17
plot.stockReturns (getReturns ), 6
plot.testPort (testPort ), 20
points ,12
points.optimalPortfolio (optimalPort ), 8
points.portReturn (portReturn ), 13
points.stockModel (stockModel ), 17
points.testPort (testPort ), 20
portCloud ,2, 10, 12
portPossCurve ,2,11, 11
portReturn ,7, 13, 21
print.optimalPortfolio (optimalPort ), 8
print.portReturn (portReturn ), 13
print.stockModel (stockModel ), 17
print.stockReturns (getReturns ), 6
print.testPort (testPort ), 20
stock04 ,2, 14, 15–17
stock94 ,2,14, 15, 16, 17stock94Info ,2,14, 15 , 16, 17
stock99 ,2,14–16 , 16
stockModel ,2,5–7,9,11–15 ,17, 17, 21
stockPortfolio
(stockPortfolio-package ), 2
stockPortfolio-package , 2
stockReturns (getReturns ), 6
summary.optimalPortfolio (optimalPort ),
8
summary.portReturn (portReturn ), 13
summary.stockModel (stockModel ), 17
summary.stockReturns (getReturns ), 6
summary.testPort (testPort ), 20
testPort ,7,9,20, 20
23