Turn a market crash into dollars for your own portfolio, two ways: a quick beta estimate and a replay of five real crises. With a worked sample and how Exent splits the loss by holding.
A first estimate is your portfolio’s value times its beta times 30%. Beta measures how much a holding has tended to move for each 1% move in the S&P 500. Your portfolio’s beta is the weighted average of your holdings’ betas.
| Sample portfolio ($100,000) | Weight | Beta (Exent data) | Weighted beta |
|---|---|---|---|
| SPY | 40% | 1.00 | 0.40 |
| QQQ | 25% | 1.22 | 0.31 |
| AAPL | 20% | 1.07 | 0.21 |
| NVDA | 15% | 2.21 | 0.33 |
| Portfolio | 100% | 1.25 |
A 30% market fall × 1.25 ≈ a 37.5% fall, or about $37,500 on $100,000. Beta is an average over a long period, mostly calm months, so treat this as a rough first number. Real crashes are less tidy, which is why the replay below matters more.
Replay each holding’s peak‑to‑trough drop in a real crisis, weight it, and convert to dollars. Sample portfolio, $100,000, drops from Exent’s data as of Sep 30, 2026:
| Crisis | SPY drop | Sample portfolio drop | Loss on $100,000 | Biggest contributor |
|---|---|---|---|---|
| 2008 financial crisis | −56.5% | −60.9% | $60,900 | SPY (37% of the loss) |
| 2018 trade war | −20.2% | −29.6% | $29,600 | NVDA (28%) |
| 2020 COVID crash | −34.1% | −32.6% | $32,600 | SPY (42%) |
| 2022 rate hikes | −25.4% | −33.8% | $33,800 | SPY (30%), NVDA close behind (27%) |
| 2025 tariff selloff | −19.0% | −24.3% | $24,300 | SPY (31%) |
Because holdings rarely hit bottom on the same day, the weighted sum is a slightly conservative figure. The method is laid out step by step on the crash test page.
Compare each holding’s share of the loss with its share of the money. In the 2022 replay, SPY was 40% of the money and 30% of the loss. Nvidia was 15% of the money and 27% of the loss: about 1.8 times its weight. A holding that punches far above its weight in a crash is the first place to look, whatever its long‑term return.
That is a crisis replay. Crash liability applies the same share-of-the-damage idea to your portfolio’s own worst 5% of months instead of a named crisis: each holding’s share of the portfolio’s loss in those months, rather than its own percentage fall.
Exent does not assume a crash size. It looks at your current portfolio’s worst 5% of months over the last 3, 5 or 8 years, and splits the loss in those months by holding (weight × that holding’s return in each month).
In Exent’s data since mid‑2016, there were 16 months in which the S&P 500 (SPY) fell more than 4%, averaging −6.7%. In those months, 1–3 month Treasury bills (BIL) averaged +0.2%, gold (GLD) −0.4% and long Treasuries (TLT) −1.9%. But no cushion works every time: TLT returned −31.2% in 2022, when rising rates hit stocks and bonds together. More in how to hedge a portfolio.
Roughly your portfolio value times its beta times 30%. A $100,000 portfolio with a beta of 1.25 would lose about $37,500, though real crashes can hit some holdings much harder than beta suggests.
Multiply each holding’s beta by its weight and add the results. Most data sites show a beta for each stock and ETF.
It is each holding’s share of the portfolio’s loss in its worst 5% of months. A holding with a share far above its weight drives more of the damage than its size suggests.
Neither predicts the next crash. The replay uses real behavior in real crises, so it shows which holdings fell far more than the market, which a single beta number can hide.
Upload a screenshot of your holdings and get concentration, overlap, crash exposure and a risk-matched benchmark in about a minute.
Educational content, not investment advice. Examples are illustrative; past performance does not guarantee future results.