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strategy-lab/to_explore/pyquantnews/24_FactorAnalysis.ipynb
David Brazda e3da60c647 daily update
2024-10-21 20:57:56 +02:00

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{
"cells": [
{
"cell_type": "markdown",
"id": "8bea070e",
"metadata": {},
"source": [
"<div style=\"background-color:#000;\"><img src=\"pqn.png\"></img></div>"
]
},
{
"cell_type": "markdown",
"id": "59b6b6e4",
"metadata": {},
"source": [
"This code performs a multifactor analysis on monthly stock returns, applying the Fama-French three-factor model for financial analysis. It fetches historical factor data, calculates active returns of selected stocks, and estimates their sensitivities to the Fama-French factors. The code also performs rolling regression to analyze the stability of factor exposures over time. Lastly, it calculates and prints the marginal contributions to risk from each factor."
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "84290a88",
"metadata": {},
"outputs": [],
"source": [
"import numpy as np\n",
"import pandas as pd"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "2ec2de24",
"metadata": {},
"outputs": [],
"source": [
"import pandas_datareader as pdr\n",
"import yfinance as yf"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "06d39571",
"metadata": {},
"outputs": [],
"source": [
"import statsmodels.api as sm\n",
"from statsmodels import regression\n",
"from statsmodels.regression.rolling import RollingOLS"
]
},
{
"cell_type": "markdown",
"id": "bc2a7be0",
"metadata": {},
"source": [
"Fetch Fama-French factors data starting from 2000-01-01 and select the SMB and HML factors"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "5aff0b52",
"metadata": {},
"outputs": [],
"source": [
"factors = pdr.get_data_famafrench(\n",
" 'F-F_Research_Data_Factors',\n",
" start='2000-01-01'\n",
")[0][1:]"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "65938e3e",
"metadata": {},
"outputs": [],
"source": [
"SMB = factors.SMB\n",
"HML = factors.HML"
]
},
{
"cell_type": "markdown",
"id": "8528b4ce",
"metadata": {},
"source": [
"Download monthly adjusted close prices for specified stocks starting from 2000-01-01"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "8518efcf",
"metadata": {},
"outputs": [],
"source": [
"data = yf.download(\n",
" ['SPY', 'MSFT', 'AAPL', 'INTC'], \n",
" start=\"2000-01-01\", \n",
" interval=\"1mo\"\n",
")['Adj Close']"
]
},
{
"cell_type": "markdown",
"id": "439951e5",
"metadata": {},
"source": [
"Calculate the monthly returns and convert them to period-based returns"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "9b300366",
"metadata": {},
"outputs": [],
"source": [
"monthly_returns = data.pct_change().to_period(\"M\")"
]
},
{
"cell_type": "markdown",
"id": "246d309b",
"metadata": {},
"source": [
"Extract the benchmark returns (SPY) and calculate active returns against the benchmark"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "f71342e4",
"metadata": {},
"outputs": [],
"source": [
"bench = monthly_returns.pop(\"SPY\")\n",
"R = monthly_returns.mean(axis=1)\n",
"active = R - bench"
]
},
{
"cell_type": "markdown",
"id": "ff54a6cb",
"metadata": {},
"source": [
"Create a DataFrame with active returns and Fama-French factors SMB and HML"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "d8ed7a12",
"metadata": {},
"outputs": [],
"source": [
"df = pd.DataFrame({\n",
" 'R': active,\n",
" 'F1': SMB,\n",
" 'F2': HML,\n",
"}).dropna()"
]
},
{
"cell_type": "markdown",
"id": "3201423a",
"metadata": {},
"source": [
"Perform Ordinary Least Squares (OLS) regression to estimate sensitivities to the factors"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "d5e1b15c",
"metadata": {},
"outputs": [],
"source": [
"b1, b2 = regression.linear_model.OLS(\n",
" df.R, \n",
" df[['F1', 'F2']]\n",
").fit().params"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "f621be1f",
"metadata": {},
"outputs": [],
"source": [
"print(f'Sensitivities of active returns to factors:\\nSMB: {b1}\\nHML: {b2}')"
]
},
{
"cell_type": "markdown",
"id": "2eab25c3",
"metadata": {},
"source": [
"Perform rolling OLS regression to estimate how factor sensitivities change over time"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "c2489be4",
"metadata": {},
"outputs": [],
"source": [
"exog_vars = [\"SMB\", \"HML\"]\n",
"exog = sm.add_constant(factors[exog_vars])\n",
"rols = RollingOLS(df.R, exog, window=12)\n",
"rres = rols.fit()\n",
"fig = rres.plot_recursive_coefficient(variables=exog_vars)"
]
},
{
"cell_type": "markdown",
"id": "f4a1b059",
"metadata": {},
"source": [
"Calculate covariance between factors and marginal contributions to active risk (MCAR) for each factor"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "ad0355a8",
"metadata": {},
"outputs": [],
"source": [
"F1 = df.F1\n",
"F2 = df.F2"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "6b0126e7",
"metadata": {},
"outputs": [],
"source": [
"cov = np.cov(F1, F2)\n",
"ar_squared = (active.std())**2\n",
"mcar1 = (b1 * (b2 * cov[0,1] + b1 * cov[0,0])) / ar_squared\n",
"mcar2 = (b2 * (b1 * cov[0,1] + b2 * cov[1,1])) / ar_squared\n",
"print(f'SMB risk contribution: {mcar1}')\n",
"print(f'HML risk contribution: {mcar2}')\n",
"print(f'Unexplained risk contribution: {1 - (mcar1 + mcar2)}')"
]
},
{
"cell_type": "markdown",
"id": "96df69b9",
"metadata": {},
"source": [
"<a href=\"https://pyquantnews.com/\">PyQuant News</a> is where finance practitioners level up with Python for quant finance, algorithmic trading, and market data analysis. Looking to get started? Check out the fastest growing, top-selling course to <a href=\"https://gettingstartedwithpythonforquantfinance.com/\">get started with Python for quant finance</a>. For educational purposes. Not investment advise. Use at your own risk."
]
}
],
"metadata": {
"jupytext": {
"cell_metadata_filter": "-all",
"main_language": "python",
"notebook_metadata_filter": "-all"
},
"kernelspec": {
"display_name": "Python 3 (ipykernel)",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.10.13"
}
},
"nbformat": 4,
"nbformat_minor": 5
}