For decades, the “4% rule” has served as a cornerstone of retirement planning: a simple, reassuring guide to help retirees avoid running out of money. But as markets evolve and retirements lengthen, so too must our strategies. Bill Bengen, the architect of the rule, has revisited his research and offered a fresh perspective that could help Australians retire with greater confidence and flexibility.
The Origins of the 4% Rule
In the early 1990s, Bengen sought to answer a pressing question: how much could retirees safely withdraw from their portfolios each year without exhausting their savings? His analysis, based on historical market data and a portfolio comprised of 50% US stocks and 50% bonds, led to the now-famous conclusion: a 4.15% withdrawal rate (rounded to 4%) would sustain around 30 years of retirement funding, even through the worst market conditions.
This rule became a powerful planning tool and rule of thumb. For example, if you wanted $50,000 per annum in retirement income, you’d need a $1.25 million portfolio ($50,000 ÷ 4%). Simple.
Why It’s Time to Revisit the Rule
While the 4% rule remains a useful benchmark, Bengen now argues it may be too conservative for many retirees. In his new book, A Richer Retirement, he introduces strategies to “supercharge” the rule, allowing for higher withdrawals without increasing risk.
By diversifying beyond the conservative 50/50 portfolio, adding small-cap and mid-cap stocks, as well as international equities (a novel idea for US-based studies), Bengen found that retirees could safely withdraw up to 4.7% per annum, and potentially even up to 5.25–5.5% in today’s environment. For someone asking how much they need to retire, that difference matters: a retiree targeting $50,000 a year would need roughly $1.06 million at a 4.7% withdrawal rate, compared with $1.25 million under the original 4% rule.
The Four “Free Kicks” of Retirement Planning
In working with retirees, we have observed four key strategies that can enhance your retirement’s financial outcomes without adding undue risk:
Diversification (the golden rule). Broaden your asset mix across and within the staple asset classes of domestic and international stocks, listed property and bonds. It’s interesting to note that this was key to Bengen’s updated research findings, which expanded his original two-asset model into a much broader mix. A narrow portfolio concentrated in one or two asset classes is more exposed to any single market downturn than one spread deliberately across several.
Regular rebalancing. Maintain your target allocation to manage risk and effectively capture portfolio gains. Left alone, a portfolio drifts over time as some assets grow faster than others, quietly shifting your risk profile without you making an active decision to take on more of it. Rebalancing periodically brings your mix back to what you actually intended.
Systematic portfolio tilts. Slightly favour quality small-cap, underpriced and consistently profitable equities to target long-term growth. This isn’t about picking individual stocks or timing the market. It’s a structural tilt within a diversified portfolio toward the segments of the market that evidence suggests offer higher expected returns over the long run.
Retirement glide path. In anticipation of your portfolio providing your lifestyle income, gradually decrease your investment in equities in favour of high credit quality and liquid bonds until your desired asset mix is achieved. This approach helps mitigate early-retirement market shocks while providing some “dry powder” (readily available cash and bonds) to take advantage of market recoveries in the future.
While some of these strategies may be beyond the management skills of many retirees, they should be easily achievable with the guidance of our advisers.
Customisation Is Key
While Bengen’s research is US-based, the maths holds true, and the principles translate well to Australian retirees, especially when adjusted for our unique financial landscape and the benefits available in our superannuation system.
However, the most important takeaway from Bengen’s updated research is this: your retirement is personal. Your spending patterns, health outlook, family dynamics, and view on risk all shape your ideal strategy. The 4% rule is a starting point, not a one-size-fits-all solution.
Working out how much super you need to retire, or how much you need to retire more broadly, depends far more on your own circumstances than on any single rule of thumb. At Capital Partners, we believe in finding your true prosperity: helping you align your wealth with your life. Whether you’re approaching retirement or already enjoying it, get in touch to speak with our retirement planning specialists about stretching your retirement rules.
Bill Bengen’s updated work, A Richer Retirement, is available now.
