Stefan Sharkansky's Adaptive Retirement Spending Formula Challenges the 4% Rule

Ph.D. statistician Stefan Sharkansky, author of the provocatively titled paper 'The Only Other Spending Rule Article You Will Ever Need' published in the Financial Analysts Journal, argues that the widely used 4% rule leads retirees to systematically underspend — leaving money on the table throughout retirement rather than actually enjoying their wealth. His alternative framework adapts withdrawals dynamically as markets change, rather than locking retirees into a fixed annual draw that ignores portfolio performance.

A central pillar of Sharkansky's approach involves building a TIPS (Treasury Inflation-Protected Securities) ladder using individual bonds rather than TIPS funds. He argues individual TIPS provide more precise inflation protection and cash flow matching than fund-based alternatives, which introduce duration risk and management overhead. This ladder component handles the fixed, predictable spending needs in retirement, while a separate stock portfolio handles discretionary or variable spending.

For stock portfolio withdrawals, Sharkansky proposes a specific formula that scales distributions to current portfolio value and market conditions — essentially a variable percentage withdrawal that rises and falls with the portfolio rather than a fixed dollar amount adjusted only for inflation. This directly addresses sequence-of-returns risk: when markets drop, you pull less; when markets are strong, you can spend more. He contrasts this with traditional Monte Carlo simulations, which he views as less reliable than historical return analysis for stress-testing retirement income plans.

Sharkansky also weighs in on global diversification for retirees, global equity exposure, and how to structure a bequest motive without sacrificing quality of life during retirement. His website, The Best Third, translates these academic ideas into practical planning tools, complementing his other platform PersonalFund.com, which offers fund cost analysis for financial advisors.