Think of concentration risk like a poker hand — if all your cards are the same suit, one bad round can hurt everything at once. Despite having 57 positions, this portfolio behaves more like a smaller number of equal-size holdings, because the largest names carry most of the weight. 'Effective N' is the honest answer to 'how diversified are we really?'

This simulator uses real historical stock prices — not estimates or averages. For each crisis period, it looks up what each of your current holdings actually returned, then weights them by your current portfolio allocation. NVDA really did fall 66% in 2022. META really did fall 76% in 2022. These numbers come from those real market events applied to your exact current portfolio.

Beta measures how much your portfolio moves for every 1% move in the stock market. A beta of 1.15 means if the market drops 10%, this portfolio is expected to drop about 11.5%. Think of it as an amplifier dial — above 1.0 means you're amplifying both gains and losses. This is expected for a growth-oriented portfolio, but it means down markets feel more severe.

Try the '2022 Rate Shock' preset — the slider caps at -30%, but the real impact estimate is shown in the Historical Crash Simulator above. This calculator uses your portfolio's beta to estimate outcomes. It's a quick approximation; real crashes are messier. The Crash Simulator uses actual stock prices instead of this formula.

Drawdown measures the journey, not just the destination. A portfolio might end the year at +10%, but if it went through a -35% drop along the way, most real investors wouldn't have stayed — they'd have sold at the bottom and locked in the loss. The recovery math is what makes drawdowns so dangerous: losing 50% requires doubling just to break even, and history shows that can take 5–6 years.

Every portfolio has pressure points — external events that cause disproportionate damage to that specific portfolio. This table maps the biggest ones for JCN's current holdings. Interest rate rises and AI sentiment shifts are at the top because so much of the portfolio is in high-multiple tech stocks that are sensitive to both. The dollar amounts help make the percentages concrete.