Risk Free Rate and Fama French factors
Throughout 2012 Risk Free Rate for US and US has consistently been one of our top posts.
For a US risk free rate, Ken French’s site provides downloadable files of Fama/French factors that include this.
On the data library page:
Scroll down to U.S. Research Returns Data (Downloadable Files)
The Fama/French Factor downloadable files are available in default/monthly, weekly or daily format.
The risk free rate in these files is based on the returns for a 1 month (4 week) Treasury Bill, and these are expressed in terms of monthly, weekly or daily returns.
For example, the monthly risk free return values include:
- 200701 – 0.44
- …
- 200801 – 0.21
For January 2007 the risk free monthly return is 0.44%, and for January 2008 0.21%
If rather than Ken French’s site you go to the FRED Economic Data (Federal Reserve Bank of St. Louis Economic Data) and download the 4-Week Treasury Bill: Secondary Market Rate (Series id TB4WK) from Board of Governors of the Federal Reserve System H15 Selected Interest Rates, they you will get a file expressing the annualised yield on a T-Bill.
For example, the monthly yield figures for TB4WK include:
- 2007-01-01 – 4.84
- …
- 2008-01-01 – 2.68
For January 2007 the annual yield on a 4-week T-Bill was 4.84% and for January 2008 2.68%
Converting annual yield to monthly return
To make an annual yield, downloaded from FRED Economic Data or Datastream or Bloomberg etc., comparable with the monthly return from the downloadable Fama/French factors we need to convert. We could use an Excel formula
4.84% annually – POWER( (1 + 4.84/100), 1/12 ) = 1.003947 – monthly return 0.39%
2.68% annually – POWER((1 + 2.68/100), 1/12 ) = 1.002206 – monthly return 0.22%
[Converting to weekly would be POWER( (1+r/100), 1/52 ) where r is the annual yield
– converting to daily POWER( (1+r/100)/1/250 ) assuming 250 trading days per year]
Key Tip
There are two important steps to finding a good proxy for the risk free rate:
- Finding a series that is as close to risk free as possible for the analysis you are doing, and where you have data available for the relevant dates.
- Comparing the data you retrieve with the data format you want and converting between an annual yield and monthly/weekly/daily return as appropriate
In academic work, we recomend that you what you have chosen for your risk free rate and any data conversion that you have applied.
For further tips on potential sources, see earlier posts Risk Free Rate for US and US and Risk Free Interest Rate.
How would you convert a 20 year risk free rate into a monthly rate?
If you want to use a 20 year bond rate as a risk free rate. The yield will usually be expressed as an annual rate. This can be converted to a monthly return as described in https://bizlib247.wordpress.com/2013/01/18/risk-free-rate-and-fama-french-factors/
The Fama-French and Momentum Portfolios and Factors in the UK are available for bona fide academic research only from the University of Exeter Xfi Centre for Finance and Investment.
http://business-school.exeter.ac.uk/research/areas/centres/xfi/research/famafrench/
Do you know where I can find daily Fama-French factors for UK as Exeter’s webpage only provides monthly and yearly data? Thank you!
I am afraid not. Exeter’s webpage is the only source of Fama-French factors for the UK that I know about.
Exeter’s webpage now includes daily monthly and annual factors – see http://business-school.exeter.ac.uk/research/areas/centres/xfi/research/famafrench/files/
Resources for accessing FRED economic data include Fred Add-In for Microsoft Excel and Embedded FRED
Sir, thank you for your response!
How should I convert the uk tbill tender 3M(UKTBTND) downloaded monthly from datastream to be comparable with the monthly Fama-French factors from Exeter’s webpage?
The Fama-French rf (risk-free) factor for December 2008 is 0.000976 (a monthly return of almost 0.1%)
The UK T-Bill tender 3M (UKTBTND) from Datastream is 1.18253 (an annual percentage yield of almost 1.2%)
To convert you can use the Excel fomula:
=POWER(1+X/100,1/12)-1 (where X is the annual yield figure from Datastream)
1.18253 (annual percentage yield)
1 + 1.18253/100 (after 1 year)
POWER(1 + 1.18253/100, 1/12) (after 1 month – root 12 to convert annual to monthly)
POWER(1 + 1.18253/100, 1/12) – 1 (monthly return)
0.000980 (to 6 decimal places)
Thank you so much for your response!
Hi, Really hope that somebody can help me out, I have struggled with this for a week now.. I have constructed quarterly portfolios, and want to test them up against Fama-French 3 factor model.. I have downloaded daily observations on Fama-French 3 factor model from French´s homepage. I Have also downloaded 3 month us treasury bills (monthly compounded) from Bloomberg. How can I adjust the RF on the Fama-French model and 3 m t-bills so that they are comparable?
Reguard frustrated Student