Wealth Planning Series · Vol. I

Retirement Probability Analysis

Longevity Modeling & Sustainable Withdrawal Assessment
Prepared by MACH96
I · Client Inputs
Establish the Parameters
Enter current ages, portfolio value, and desired annual retirement income. Spouse inputs are optional.
A
Primary Client
B
Spouse / Partner
C
Investable Portfolio
D
Income Objective
Plan Parameters
Withdrawal Rate
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Joint Life Expectancy
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Probability of Success
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II · Longevity Projection
Life Expectancy & Survival
Per the SSA Period Life Table — Social Security Administration, 2022 mortality data (2025 Trustees Report).
Survival Probability Curve
Longevity Milestones
III · Withdrawal Analysis
Rate Versus Sustainable Benchmarks
Reference: Morningstar — "The State of Retirement Income," 2025 Edition (December 2025). Benchmarks reflect a 90% probability of portfolio survival.
Withdrawal Rate vs. Morningstar Safe Withdrawal Benchmarks
2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0%
IV · Success Probability
Plan Outcomes Across Horizons
Probability the portfolio sustains the requested real income — derived from Monte Carlo simulation at three longevity benchmarks (50th, 25th, and 5th percentile).
Portfolio Path Simulations · Real (Inflation-Adjusted) Dollars
Plan Interpretation
Math Behind the Number
Simulation Methodology
Simulations Run
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Independent paths per scenario
Expected Real Return
3.8%
After inflation, balanced portfolio
Annualized Volatility
8.5%
Standard deviation of real returns
Return Distribution
Normal
Box-Muller transform, IID draws
Each scenario simulates 10,000 independent retirement paths. In each path, annual portfolio returns are drawn from a Normal distribution; constant real withdrawals are deducted at year-end. Success is defined as the portfolio retaining positive value at the end of the planning horizon. Parameters are calibrated such that a 3.9% withdrawal over 30 years produces approximately 90% success — matching Morningstar's 2025 base case.