Traditional spreadsheets break down when executing complex statistical modeling or handling datasets exceeding millions of rows. Python and R provide scalable alternatives.
Statistical Frameworks & Time-Series Modeling
Financial analysis relies on time-series forecasting to predict revenues, cash flows, and market risks.
- Autoregressive Integrated Moving Average (ARIMA): Models linear time-series dependencies based on past values and lagging forecast errors.
- Generalized Autoregressive Conditional Heteroskedasticity (GARCH): Models and forecasts time-varying asset volatility, which is vital for options pricing and Value-at-Risk calculations.
Python Risk & Portfolio Optimization Script
python
import numpy as np
import pandas as pd
# Simulating historical returns for a three-asset portfolio
np.random.seed(42)
returns = pd.DataFrame(np.random.normal(0.0005, 0.012, (1000, 3)), columns=['Equities', 'Bonds', 'Real_Estate'])
# Portfolio Weights
weights = np.array([0.5, 0.3, 0.2])
# Calculate Expected Portfolio Return and Variance
portfolio_return = np.sum(returns.mean() * weights) * 252
portfolio_covariance = returns.cov() * 252
portfolio_variance = np.dot(weights.T, np.dot(portfolio_covariance, weights))
portfolio_volatility = np.sqrt(portfolio_variance)
# Compute Historical Value at Risk (VaR) at 95% confidence level
portfolio_daily_returns = returns.dot(weights)
historical_var_95 = np.percentile(portfolio_daily_returns, 5)
print(f"Annualized Return: {portfolio_return:.2%}")
print(f"Annualized Volatility: {portfolio_volatility:.2%}")
print(f"Daily Historical VaR (95%): {historical_var_95:.2%}")