What it means
Monte Carlo simulation takes a sample of historical trade outcomes (or a model of trade outcomes) and randomly reorders them thousands of times to generate a distribution of possible equity curves. The output: percentile bands showing expected max drawdown, time-to-double-equity, probability of various ruin thresholds. Reveals tail-risk that single backtest paths hide because they show only ONE realized order of trades.
Why it matters
A backtest shows what happened with one specific trade order. Monte Carlo shows what could have happened with 10,000 reorderings of the same trade set. The 95th-percentile worst drawdown from Monte Carlo is typically 1.3-2x the backtest's actual maximum drawdown — meaning your live drawdown can be materially worse than backtest suggests just due to unlucky ordering.
How to use it
After backtest, run Monte Carlo on the trade-list with thousands of random reorderings. Use the 95th-percentile max drawdown as your planning number, not the backtest's actual max drawdown. Size positions assuming this larger drawdown could occur. Most retail traders skip this step and are surprised when live drawdown exceeds backtest.
Want a worked example or a deeper dive? Ask Rocky how this concept applies to your specific watchlist or trade idea.
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