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The 4 Percent Rule in Retirement: Is It Still Valid?

The 4% rule has been the most widely cited guideline in retirement income planning for over three decades.

Moore Invested

It originated from William Bengen’s 1994 research showing that a retiree could withdraw 4% of their initial portfolio in year one, then adjust that dollar amount for inflation each subsequent year, and survive any 30-year retirement period in U.S. market history. However, the rule was developed under different market conditions and was not designed to be a one-size-fits-all answer. Bengen himself has since revised his estimate upward to a historical maximum safe withdrawal rate of 4.7% based on expanded data. Meanwhile, Morningstar’s most current research from December 2025 puts the conservative baseline at 3.9% for retirees seeking consistent inflation-adjusted spending from a balanced portfolio over 30 years, up from 3.7% the prior year. The 4% rule remains a useful starting point for estimating how much you need to save, but it should not be treated as a guaranteed formula. Market conditions, portfolio composition, retirement length, healthcare costs, and spending flexibility all matter. The most reliable approach is a dynamic withdrawal strategy built around your actual income needs and circumstances.

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