Daily Risk Free Rate (based on 3-Month US Treasury Bills Rates)

riskfree.py

import yfinance as yf
import pandas as pd

# de-annualize yearly interest rates
def deannualize(annual_rate, periods=365):
    return (1 + annual_rate) ** (1/periods) - 1

def get_risk_free_rate():
    # download 3-month us treasury bills rates
    annualized = yf.download("^IRX")["Adj Close"]
    
    # de-annualize
    daily = annualized.apply(deannualize)

    # create dataframe
    return pd.DataFrame({"annualized": annualized, "daily": daily})    

if __name__ == "__main__":
    rates = get_risk_free_rate()
    print(rates.tail())

divide Adj Close values by 100 before passing through function, no?