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Writer's pictureAlpesh Patel

The 4% Rule: What You Need to Know for a Safe Retirement Withdrawal Strategy

The Trinity Study is a widely cited research in personal finance and retirement planning. It was conducted by three professors from Trinity University in 1998, and the study analysed historical stock and bond returns to determine a "safe withdrawal rate" for retirees from their investment portfolios.


The main goal of the study was to find out how much retirees could safely withdraw from their portfolios each year without running out of money. The study focused on periods of 30 years and concluded that a 4% withdrawal rate was generally safe, meaning retirees could withdraw 4% of their portfolio in the first year of retirement, adjust the amount for inflation each year, and have a high likelihood of not depleting their funds over 30 years.


Key Concepts of the Trinity Study:

  1. Safe Withdrawal Rate (SWR): The percentage of the portfolio a retiree can withdraw annually without running out of funds.

  2. Asset Allocation: The mix of stocks and bonds in a portfolio impacts its longevity and the safe withdrawal rate.

  3. Success Rate: The probability of a retiree’s portfolio lasting through their retirement period. A 4% withdrawal rate typically provided success rates over 90% in the study.


Updated Insights

Since the original study, the financial landscape has changed with lower bond yields and fluctuating stock markets. Some analysts argue that a 3.5% or even 3% withdrawal rate might be more appropriate in today’s market to provide more safety, especially given longer life expectancies and economic volatility.


Example Scenarios:

  • Scenario 1: A retiree has a $1 million portfolio, split 60% in stocks and 40% in bonds. With a 4% withdrawal rate, they would take out $40,000 in the first year of retirement. Each year, they would adjust the amount withdrawn for inflation.

  • Scenario 2: If the same retiree chooses a more conservative 3% withdrawal rate, they would take out $30,000 in the first year but would likely reduce the risk of running out of money over a longer retirement period.



Here is the graphical representation of success rates for different portfolio allocations and the 4% withdrawal rate. This graph can be useful in illustrating the varying levels of risk depending on the mix of stocks and bonds in a retirement portfolio. Conclusion

For individuals planning their retirement, the Trinity Study offers valuable insights into how much you can safely withdraw from your portfolio without running out of money. A 4% withdrawal rate has been historically effective, but in today’s low-interest environment, some experts suggest being more conservative, aiming for 3%–3.5% to account for increased longevity and market volatility.


The study highlights the importance of having a balanced portfolio of stocks and bonds, where the right mix can significantly increase the probability of your savings lasting through retirement.

Using this information can help ensure a more secure and sustainable retirement plan.This practical guidance helps you make more informed decisions about your investments and retirement strategy. Academic References for Further Reading:

  1. Bengen, W.P. (1994) - "Determining Withdrawal Rates Using Historical Data," Journal of Financial Planning. This article introduced the "4% rule" concept.

  2. Cooley, P.L., Hubbard, C.M., & Walz, D.T. (1998) - "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable," AAII Journal. This is the original Trinity Study.

  3. Pfau, W.D. (2013) - "A Broader Framework for Determining an Efficient Frontier for Retirement Income," Journal of Financial Planning. A more recent take on safe withdrawal rates, accounting for market volatility and bond yields.

  4. Kitces, M. (2020) - "The 4% Rule Is Not Safe in a Low-Yield World," Journal of Retirement. An analysis of withdrawal rates in today’s low-interest environment.


Alpesh Patel OBE



Disclaimer: The content provided on this blog is for informational purposes only and does not constitute financial advice. The opinions expressed here are the author's own and do not reflect the views of any associated companies. Investing in financial markets involves risk, including the potential loss of your invested capital. Past performance is not indicative of future results. 


You should not invest money that you cannot afford to lose. Mentions of specific securities, investment strategies, or financial products do not constitute an endorsement or recommendation. The author may hold positions in the securities discussed, but these should not be viewed as personalised investment advice.  


Readers are encouraged to conduct their own research and seek professional advice before acting on any information provided in this blog. The author is not responsible for any investment decisions made based on the content of this blog.

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