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The basics
The baseline gives each account the return path written in the plan. Market Simulator can instead make selected non-cash accounts live through the real annual returns of a chosen index. You choose both the historical calendar year that begins the sequence and the plan year where that sequence lands.
Illustrative numbers
Landing 2008 on the first retirement year
Historical sequenceS&P 500 total return beginning in 2008
Where it landsThe first retired plan year
Accounts following itSelected investment accounts; cash stays on its own rate
The selected accounts experience 2008 and the years after it in their historical order. The engine then settles spending, withdrawals, tax, sales, and later balances from that changed path; it does not merely redraw the investment line.
Calculation transparency
How it works in MoneyWhatIf
- 01
With the simulator off, each account keeps the annual return path configured on that account. With it on, each eligible selected account reads one chosen historical series instead.
- 02
The chosen calendar start year is matched to the chosen plan year. Years before that landing keep the account’s configured return, and years after the historical series runs out fall back to that return rather than looping history.
- 03
The same historical years are applied to every selected account so a market shock reaches the household together. Cash accounts cannot follow an index, and any eligible account can be left out deliberately.
- 04
A total-return series already includes reinvested distributions. For a price-only series, the model adds the account’s modeled equity yield; account fees are deducted from either path.
- 05
The named-crisis shortcuts choose a historical starting year and, when the plan has a retirement, land it on the first retired year. The sequence continues through the recovery instead of stopping at the trough.
- 06
Every change reruns the funded annual plan, so contributions, withdrawals, taxes, required distributions, property sales, shortfalls, and ending balances respond to the market path.
Keep in mind
Model limits
A historical replay is one scenario, not a forecast or a probability that the same path will recur.
The model uses annual returns and annual cash-flow timing; it cannot show an intra-year crash, recovery, trade, or panic sale.
An index is a proxy, not a household’s exact holdings. Results depend on the selected series, account scope, fees, yield treatment, and the plan assumptions that take over outside the data’s coverage.
This explanation documents the planning model. It is educational, not individualized tax, legal, Medicare, or investment advice.
Where it appears
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See this concept in context, with a guide to each page and its controls.
The words behind it
Related financial terms
Plain-English definitions, with 2026 figures and worked examples, from the financial terms glossary.