knitr::opts_chunk$set(echo = TRUE)
library(tidyquant)
## Registered S3 method overwritten by 'quantmod':
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##   as.zoo.data.frame zoo
## ── Attaching core tidyquant packages ─────────────────────── tidyquant 1.0.11 ──
## ✔ PerformanceAnalytics 2.0.8      ✔ TTR                  0.24.4
## ✔ quantmod             0.4.28     ✔ xts                  0.14.1
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## ✖ PerformanceAnalytics::legend() masks graphics::legend()
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## ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors
library(PortfolioAnalytics)
## Warning: package 'PortfolioAnalytics' was built under R version 4.5.3
## Loading required package: foreach
## Warning: package 'foreach' was built under R version 4.5.3
## Registered S3 method overwritten by 'PortfolioAnalytics':
##   method           from
##   print.constraint ROI
library(tidyr)
library(dplyr)
## Warning: package 'dplyr' was built under R version 4.5.3
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## Attaching package: 'dplyr'
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library(lubridate)
## 
## Attaching package: 'lubridate'
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library(xts)
library(ROI)
## Warning: package 'ROI' was built under R version 4.5.3
## ROI: R Optimization Infrastructure
## Registered solver plugins: nlminb, symphony, glpk, quadprog.
## Default solver: auto.
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## Attaching package: 'ROI'
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## 
##     is.constraint, objective
library(ROI.plugin.quadprog)
## Warning: package 'ROI.plugin.quadprog' was built under R version 4.5.3
# 1. Define Defensive Tickers and Benchmark
tickers <- c('PG', 'KO', 'JNJ', 'NEE', 'JPM', 'XOM')
benchmark_ticker <- 'SPY'
start_date <- Sys.Date() - years(3)

# 2. Pull and Format Returns
prices <- tq_get(tickers, from = start_date, get = "stock.prices")
returns_wide <- prices %>%
  group_by(symbol) %>%
  tq_transmute(select = adjusted, mutate_fun = periodReturn, period = "daily", col_rename = "Ra") %>%
  pivot_wider(names_from = symbol, values_from = Ra)

returns_multi <- na.omit(xts(returns_wide[,-1], order.by = as.Date(returns_wide$date)))

# 3. Formulate Global Minimum Variance Constraints (Min Volatility)
port_spec <- portfolio.spec(assets = tickers) %>%
  add.constraint(type = "full_investment") %>%                  
  add.constraint(type = "long_only") %>%                        
  add.constraint(type = "box", min = 0.05, max = 0.25) %>% # Min 5%, Max 25% for diversification
  add.objective(type = "risk", name = "StdDev")            # Objective: MINIMIZE Volatility Only

# 4. Optimize
opt_weights <- optimize.portfolio(R = returns_multi, portfolio = port_spec, optimize_method = "ROI")
portfolio_weights <- extractWeights(opt_weights)

# 5. Run Backtest vs Benchmark
portfolio_returns <- Return.portfolio(returns_multi, weights = portfolio_weights)
colnames(portfolio_returns) <- "Defensive_LowVol_Portfolio"

benchmark_prices <- tq_get(benchmark_ticker, from = start_date, get = "stock.prices")
benchmark_wide <- benchmark_prices %>%
  tq_transmute(select = adjusted, mutate_fun = periodReturn, period = "daily", col_rename = "SPY")
benchmark_returns <- xts(benchmark_wide$SPY, order.by = as.Date(benchmark_wide$date))

combined_returns <- na.omit(merge.xts(portfolio_returns, benchmark_returns))

# 6. Performance Reports
print(table.AnnualizedReturns(combined_returns))
##                           Defensive_LowVol_Portfolio benchmark_returns
## Annualized Return                             0.1736            0.2285
## Annualized Std Dev                            0.1144            0.1513
## Annualized Sharpe (Rf=0%)                     1.5177            1.5098
print(table.DownsideRisk(combined_returns))
##                               Defensive_LowVol_Portfolio benchmark_returns
## Semi Deviation                                    0.0052            0.0067
## Gain Deviation                                    0.0047            0.0070
## Loss Deviation                                    0.0051            0.0072
## Downside Deviation (MAR=210%)                     0.0103            0.0113
## Downside Deviation (Rf=0%)                        0.0049            0.0064
## Downside Deviation (0%)                           0.0049            0.0064
## Maximum Drawdown                                  0.1021            0.1876
## Historical VaR (95%)                             -0.0108           -0.0141
## Historical ES (95%)                              -0.0151           -0.0210
## Modified VaR (95%)                               -0.0112           -0.0078
## Modified ES (95%)                                -0.0219           -0.0078
cat("Beta:", CAPM.beta(portfolio_returns, benchmark_returns), "\n")
## Beta: 0.3283651
cat("Alpha (Ann.):", CAPM.alpha(portfolio_returns, benchmark_returns) * 252, "\n")
## Alpha (Ann.): 0.09531583