Card Monte Carlo Simulator
Pick a card, choose a volatility profile, run 10,000 simulated price paths. See the full distribution of outcomes — not just the expected price. Understand the downside risk before you buy.
How to read the results
- Median (P50): half the paths end above this, half below. Your "middle case" outcome.
- 5th percentile (P5): pessimistic scenario. Only 5% of simulated outcomes are worse than this number.
- 95th percentile (P95): optimistic scenario. Only 5% of outcomes are better than this.
- Probability of gain: share of paths ending above the starting price.
- Target hit %: share of paths that touch or exceed your target price at any time during the horizon (path-dependent).
- Histogram: shape of the final-price distribution. Wide and flat = high uncertainty. Tall and narrow = tight range.
Preset volatility profiles
Frequently asked
What is a Monte Carlo simulation and why use it for cards?
Monte Carlo simulation runs thousands of random price paths forward in time using a volatility model (geometric Brownian motion). Instead of showing a single "expected price" it shows the full distribution of possible outcomes — a 5% chance price falls below $X, a 50% chance price lands at $Y, a 5% chance price exceeds $Z. For card investors this is powerful: a card with a high expected return can still have a 30% chance of losing 40% of its value. One-number forecasts hide that risk; Monte Carlo reveals it.
How do I pick volatility and drift for my card?
Volatility (annualized standard deviation of returns) typically ranges from 15% for blue-chip vintage (1952 Mantle) to 60%+ for speculative modern rookies. Drift (expected annual return) typically ranges from -5% (declining players) to +25% (hot rookies). Use the presets — Vintage Blue-Chip (15% vol, 6% drift), HoF Veteran (25% vol, 8%), Modern RC Established (35% vol, 10%), Modern RC Speculative (55% vol, 15%), Prospect Lottery Ticket (70% vol, 20% drift with fat tails). These are calibrated to realistic hobby ranges based on historical card-price data. You can override any preset.
Are simulation outputs predictions?
No. This is a probability model, not a forecast. The simulation answers "given these assumptions about volatility and drift, what is the range of outcomes a year from now?" The assumptions are yours — if you believe LeBron has 40% volatility, the simulation shows what that implies. If actual volatility turns out to be 20%, reality will be tighter than the simulation shows. Use it to stress-test whether you are comfortable with the downside before buying, not to time the market.
What is geometric Brownian motion and is it the right model?
Geometric Brownian motion is the mathematical framework used in Black-Scholes option pricing. It assumes log-returns are normally distributed, which means prices can never go negative (good for cards) and that percent moves are symmetric (a 10% gain is as likely as a 10% loss at mean drift). It is imperfect for cards because hobby prices can have "fat tails" (crash events, Top Rookie injuries) that GBM underweights. The model is still useful as a first-order risk sketch, but treat the 1st/99th percentiles as "slightly wider in reality."
Can I simulate a card I already own?
Yes. Search any card from the 9,840-card CardVault database and the tool pre-fills its current estimated raw value as the starting price. Then pick a preset or set volatility/drift manually. You can also enter a custom starting price for graded copies (e.g., 350 for a PSA 9) and override the raw-based default.
What does the "Probability of reaching target price" mean?
Set a target price (e.g., 2x your current value). The simulation counts how many of the 10,000 paths touch or exceed that target at any point during the time horizon (path-dependent). This is more useful than just checking the final price, because it captures "the card hit 2x, then pulled back" scenarios that a point-in-time check would miss.