Common financial return and risk metrics in Python.

Installation

empyrical requires Python 3.7+. You can install it using pip:

pip install empyrical-reloaded

or conda:

conda install empyrical-reloaded -c ml4t -c ranaroussi

empyrical requires and installs the following packages while executing the above commands:

• numpy>=1.9.2
• pandas>=1.0.0
• scipy>=0.15.1
• pandas-datareader>=0.4
• yfinance>=0.1.59

Empyrical uses yfinance to download price data from Yahoo! Finance and pandas-datareader to access Fama-French risk factors.

Usage

Simple Statistics

Empyrical computes basic metrics from returns and volatility to alpha and beta, Value at Risk, and Shorpe or Sortino ratios.

import numpy as np
from empyrical import max_drawdown, alpha_beta

returns = np.array([.01, .02, .03, -.4, -.06, -.02])
benchmark_returns = np.array([.02, .02, .03, -.35, -.05, -.01])

# calculate the max drawdown
max_drawdown(returns)

# calculate alpha and beta
alpha, beta = alpha_beta(returns, benchmark_returns)

Rolling Measures

Empyrical also aggregates returna nd risk metrics for rolling windows:

import numpy as np
from empyrical import roll_max_drawdown

returns = np.array([.01, .02, .03, -.4, -.06, -.02])

# calculate the rolling max drawdown
roll_max_drawdown(returns, window=3)

Pandas Support

Empyrical also works with both NumPy arrays and Pandas data structures:

import pandas as pd
from empyrical import roll_up_capture, capture

returns = pd.Series([.01, .02, .03, -.4, -.06, -.02])
factor_returns = pd.Series([.02, .01, .03, -.01, -.02, .02])

# calculate a capture ratio
capture(returns, factor_returns)
-0.147387712263491

Fama-French Risk Factors

Empyrical downloads Fama-French risk factors from 1970 onward:

import empyrical as emp

risk_factors = emp.utils.get_fama_french()

risk_factors.head().append(risk_factors.tail())

                           Mkt-RF     SMB     HML       RF     Mom
Date
1970-01-02 00:00:00+00:00  0.0118  0.0131  0.0100  0.00029 -0.0341
1970-01-05 00:00:00+00:00  0.0059  0.0066  0.0072  0.00029 -0.0152
1970-01-06 00:00:00+00:00 -0.0074  0.0010  0.0020  0.00029  0.0040
1970-01-07 00:00:00+00:00 -0.0015  0.0039 -0.0032  0.00029  0.0011
1970-01-08 00:00:00+00:00  0.0004  0.0018 -0.0015  0.00029  0.0033
2021-02-22 00:00:00+00:00 -0.0112 -0.0009  0.0314  0.00000 -0.0325
2021-02-23 00:00:00+00:00 -0.0015 -0.0128  0.0090  0.00000 -0.0185
2021-02-24 00:00:00+00:00  0.0115  0.0120  0.0134  0.00000 -0.0007
2021-02-25 00:00:00+00:00 -0.0273 -0.0112  0.0087  0.00000 -0.0195
2021-02-26 00:00:00+00:00 -0.0028  0.0072 -0.0156  0.00000  0.0195

Asset Prices and Benchmark Returns

Empyrical yfinance to download price data from Yahoo! Finance. To obtain the S&P returns since 1950, use:

import empyrical as emp

symbol = '^GSPC'
returns = emp.utils.get_symbol_returns_from_yahoo(symbol,
                                                  start='1950-01-01')

import seaborn as sns  # requires separate installation
import matplotlib.pyplot as plt  # requires separate installation

fig, axes = plt.subplots(ncols=2, figsize=(14, 5))

with sns.axes_style('whitegrid'):
    returns.plot(ax=axes[0], rot=0, title='Time Series', legend=False)
    sns.histplot(returns, ax=axes[1], legend=False)
axes[1].set_title('Histogram')
sns.despine()
plt.tight_layout()
plt.suptitle('Daily S&P 500 Returns')

Documentation

See the documentation for details on the API.

Support

Please open an issue for support.

Contributing

Please contribute using Github Flow. Create a branch, add commits, and open a pull request.

Testing

• install requirements
  • "pytest>=6.2.0",

pytest tests