risk.cont.12jan2016.R

# R code re: CapitalSpecator.com post on risk-contribution analysis:
# "Portfolio Analysis in R: Part VI | Risk-Contribution Analysis"
# http://www.capitalspectator.com/portfolio-analysis-in-r-part-vi-risk-contribution-analysis/
# 12 Jan 2016
# By James Picerno
# http://www.capitalspectator.com/
# (c) 2016 by Beta Publishing LLC

library(quantmod)
library(tseries)
library(PerformanceAnalytics)
library(xts)
library(timeSeries)
library(TTR)

# download fund prices
symbols <-c("SPY","IJS","EFA","EEM","IEF","LQD","VWEHX","RPIBX","PREMX","QRAAX","VGSIX")
getSymbols(symbols, src='yahoo', from='2003-12-31')

for(symbol in symbols) {
  x <- get(symbol)
  indexFormat(x) <- '%Y-%m-%d'
  colnames(x) <- gsub("x",symbol,colnames(x))
  x <- x[,6]
  assign(symbol,x)
}
  
# merge price histories into one data set   
prices <- do.call(merge, lapply(symbols, get))
colnames(prices) <-c(symbols)

# generate daily return series for funds
returns <-na.omit(ROC(prices,1,"discrete"))
colnames(prices) <-c("spy","ijs","efa","eem","ief","lqd","vwehx","rpibx","premx","qraax","vgsix")

# set asset allocation weights
w = c(0.25,0.05,0.20,0.05,0.10,0.10,0.05,0.05,0.05,0.05,0.05)

# calculate risk contribution to portfolio with function from PortfolioAnalytics package
port.sd <-StdDev(returns, weights = w, portfolio_method = "component")

### END