Simulations
What it does
Simulations runs Monte Carlo models on your portfolio to show a range of plausible future outcomes — not a single number, but a distribution. You see best-case, worst-case, and the most likely band, given your current holdings and chosen assumptions.
When to use it
- You’re trying to size a position and want to see how it changes the risk profile.
- You’re answering “can my portfolio fund X by Y?” for a financial goal.
- You want to stress-test the rebalance plan from Restructuring before acting.
- You want a feel for drawdowns you might experience, not just expected returns.
How to use it
- Open Simulations from the sidebar.
- Pick the portfolio to simulate (your current portfolio, a saved restructuring plan, or a custom allocation).
- Set parameters — time horizon, expected return assumptions, volatility, contributions/withdrawals if relevant.
- Click Run simulation.
- The output shows:
- The distribution of ending values — typically a fan chart with percentile bands.
- Worst / median / best outcomes.
- Probability of meeting a target if you set one.
Tips & gotchas
- Garbage in, garbage out. The output is only as honest as the assumptions. Don’t pick optimistic returns just to feel better.
- Distributions are not predictions. A 90th-percentile path is a possibility, not a plan.
- Run multiple scenarios. Vary return and volatility assumptions to see how sensitive the result is.
- Long horizons amplify uncertainty. Don’t be surprised by wide bands at 20+ years.
Related
- Restructuring — generate the allocation, then test it here.
- Holdings — the portfolio being simulated.
- Glossary — Monte Carlo, drawdown, percentile.