Files
OpenBB/gamestonk_terminal/stocks/quantitative_analysis/factors_model.py
2021-10-30 12:52:03 -04:00

102 lines
2.9 KiB
Python

"""Factors model"""
__docformat__ = "numpy"
from urllib.request import urlopen
from zipfile import ZipFile
from io import BytesIO
from typing import Tuple
import statsmodels.api as sm
import yfinance as yf
import pandas as pd
def get_fama_raw() -> pd.DataFrame:
"""Gets base Fama French data to calculate risk
Returns
----------
fama : pd.DataFrame
A data with fama french model information
"""
with urlopen(
"http://mba.tuck.dartmouth.edu/pages/faculty/ken.french/ftp/F-F_Research_Data_Factors_CSV.zip"
) as url:
# Download Zipfile and create pandas DataFrame
with ZipFile(BytesIO(url.read())) as zipfile:
with zipfile.open("F-F_Research_Data_Factors.CSV") as zip_open:
df = pd.read_csv(
zip_open,
header=0,
names=["Date", "MKT-RF", "SMB", "HML", "RF"],
skiprows=3,
)
df = df[df["Date"].apply(lambda x: len(str(x).strip()) == 6)]
df["Date"] = df["Date"].astype(str) + "01"
df["Date"] = pd.to_datetime(df["Date"], format="%Y%m%d")
df["MKT-RF"] = pd.to_numeric(df["MKT-RF"], downcast="float")
df["SMB"] = pd.to_numeric(df["SMB"], downcast="float")
df["HML"] = pd.to_numeric(df["HML"], downcast="float")
df["RF"] = pd.to_numeric(df["RF"], downcast="float")
df["MKT-RF"] = df["MKT-RF"] / 100
df["SMB"] = df["SMB"] / 100
df["HML"] = df["HML"] / 100
df["RF"] = df["RF"] / 100
df = df.set_index("Date")
return df
def get_historical_5(ticker: str):
"""Get 5 year monthly historical performance for a ticker with dividends filtered
Parameters
----------
ticker : str
A ticker in string form
Returns
----------
data : pd.DataFrame
A dataframe with historical information
"""
tick = yf.Ticker(ticker)
df = tick.history(period="5y", interval="1mo")
df = df[df.index.to_series().apply(lambda x: x.day == 1)]
df = df.drop(["Dividends", "Stock Splits"], axis=1)
df = df.dropna()
return df
def capm_information(ticker) -> Tuple[float, float]:
"""Provides information that relates to the CAPM model
Parameters
----------
ticker : str
A ticker in string form
Returns
----------
beta : float
The beta for a stock
sys : float
The systematic risk for a stock
"""
df_f = get_fama_raw()
df_h = get_historical_5(ticker)
df = df_h.join(df_f)
df = df.dropna()
df["Monthly Return"] = df["Close"].pct_change()
df["Excess Monthly Return"] = df["Monthly Return"] - df["RF"]
df["Excess MKT-RF"] = df["MKT-RF"] - df["RF"]
df = df.dropna()
y = df[["Excess Monthly Return"]]
x = df["Excess MKT-RF"]
x = sm.add_constant(x)
model = sm.OLS(y, x).fit()
beta = model.params["Excess MKT-RF"]
sy = model.rsquared
return beta, sy