What If? Buy-Timing Simulator
See how your 401(k) returns change depending on which day of the settlement cycle your money buys shares.
Configure Your Simulation
Time period
Starting investment
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Buy day presets
Portfolio Value by Buy Day
Final portfolio value from $10,000 invested at each buy-day lag. Lag 0 = paycheck day, lag 10 = two full weeks later.
Head-to-Head Comparison
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Optimal (lag +3)
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Typical 401(k) (lag +8)
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Difference
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Era Comparison
How the optimal vs. typical settlement timing played out across different periods of 401(k) history:
| Era | Lag +3 (optimal) | Lag +8 (typical) | Difference | Advantage |
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Personal Cost Calculator
Estimate how much settlement timing drag could cost your 401(k) over your career.
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Your annual 401(k) equity contribution
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Estimated annual drag from settlement timing
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Lifetime cost (with compounding)
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Percentage of retirement savings
These estimates use the 2000-2019 era coefficients when the effect was strongest. The actual cost depends on your employer's specific clearing timeline and whether the pattern persists.