With a market capitalization (market cap) of $1.05B — a measure of how much the company is worth — Castle Biosciences, Inc. ranks #2,454 among the 2,493 companies tracked, and 344th in Healthcare as of October 11, 2026. Shares trade at $34.42, up 2.11% on the day.
of 2,493 tracked
Market-cap change uses historical capitalization records. Share-price returns are a different series — they can diverge when the share count changes. Those returns are not a CAGR until you pick a start value, an ending value, and years. CAGR calculator. Market cap vs. stock price.
Year-end values and the chart both come from historical market-cap records, not from applying today's share count to past prices. Latest historical observation October 9, 2026. Ranking headline cap is the snapshot figure as of October 11, 2026.
| Year | As of | Market cap | Annual change | Year-end close |
|---|---|---|---|---|
| 2026 | Oct 9, 2026 | $1.05B | -10.01% | $34.42 |
| 2025 | Dec 31, 2025 | $1.16B | +52.50% | $38.90 |
| 2024 | Dec 31, 2024 | $762.43M | +30.16% | $26.65 |
| 2023 | Dec 29, 2023 | $585.76M | -5.74% | $21.58 |
Ranking figure $1.05B as of October 11, 2026.
Castle Biosciences, Inc.'s ranking market cap is the provider-reported capitalization on the same snapshot as the rest of this site, with a share price of $34.42 as of October 9, 2026. Charts and the year-end table use a separate historical market-cap series, last observed at $1.05B on October 9, 2026. See how the ranking works.
Live shares outstanding are not on the quote used for price, so this page does not invent a current share count. Shares outstanding vs. float.
The latest annual report (FY 2025) used a weighted-average 28,986,000 shares. That figure is an average for the year, not the live count in the market-cap formula.
Multiplying the latest price by those FY 2025 weighted-average shares would give about $997.7M. The ranking uses the provider's reported market cap instead, which reflects a current share count rather than that annual average.
Book equity: assets minus liabilities on the latest annual report.
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FY 2025 net worth
Largest U.S.-listed names in the same FMP sector — not a hand-picked competitor set.
| Rank | Company | Market cap | 1D |
|---|---|---|---|
| #14 | Eli Lilly and Company LLY | $1.11T | +0.83% |
| #21 | Johnson & Johnson JNJ | $630.04B | +1.93% |
| #24 |
Castle Biosciences, Inc. functions as a commercial-stage diagnostics firm, with its primary objective being the provision of both diagnostic and prognostic testing services, specifically targeting various dermatological cancers. Their flagship product, DecisionDx-Melanoma, represents an advanced multi-gene expression profile (GEP) assay engineered to assess the probability of metastasis in patients afflicted with invasive cutaneous melanoma. In addition to their leading solution, the company has created several other specialized, proprietary tests.
Summary from the company profile (Financial Modeling Prep). Principal financial figures above are for FY 2025.
Visit websiteAs of October 11, 2026, Castle Biosciences, Inc. (CSTL) is worth $1.05B — that is its market capitalization, the total value of its outstanding shares on MarketCapLens.
A company’s net worth is its shareholders’ equity: assets minus liabilities on the balance sheet. That is book equity, not market cap. For FY 2025, Castle Biosciences, Inc.’s book equity is about $470.87M. Market cap is the market value of the outstanding shares. As of October 11, 2026, its market cap is $1.05B. Book equity is an accounting remainder; market cap is a trading value. Neither is a person’s net worth.
Castle Biosciences, Inc. ranks #2,454 among the 2,493 companies tracked on MarketCapLens. In Healthcare it ranks #344 of 353.
Fundamentals are annual. Figures labeled with their fiscal year. Live ratios use the current price against those annual earnings.
Over the past year, market cap and share price moved by different amounts. Share count can change independently of price. What changes market cap.
| 2022 |
|---|
| Dec 30, 2022 |
| $621.46M |
| -42.98% |
| $23.54 |
| 2021 | Dec 31, 2021 | $1.09B | — | $42.87 |
|---|
Last observation of each calendar year from historical market-cap records. The current year is through the latest date, not a completed year-end. Share-price close is the matching session for context — we do not rebuild cap from today's share count.
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FY 2025
| $488.47B |
| +1.49% |
| #36 | Merck & Co., Inc. MRK | $359.61B | +2.26% |
| #38 | UnitedHealth Group Incorporated UNH | $344.46B | +2.25% |
| #49 | Novartis AG NVS | $273.23B | +0.45% |
Companies immediately above and below in the overall ranking. They may be in a different sector.
| Rank | Company | Market cap | 1D |
|---|---|---|---|
| #2451 | Tuya Inc. TUYA | $1.05B | +1.18% |
| #2452 | Heritage Insurance Holdings, Inc. HRTG | $1.05B | -1.14% |
| #2453 | Maiden Holdings North America, Ltd. MHNC | $1.05B | 0.00% |
| #2455 | MannKind Corporation MNKD | $1.05B | -3.80% |
| #2456 | Cadre Holdings, Inc. CDRE | $1.05B | -1.13% |
| #2457 | Cementos Pacasmayo S.A.A. CPAC | $1.05B | +0.16% |
Castle Biosciences, Inc.’s ranking market cap of $1.05B comes from the same snapshot as the rest of this site, as of October 11, 2026. It is not share price multiplied by the FY 2025 weighted-average share count of 28,986,000. The historical market-cap series last observed $1.05B on October 9, 2026.
Over the past year, Castle Biosciences, Inc.’s market cap is up 50.76%, using historical market-cap records rather than today’s share count applied to past prices.
Castle Biosciences, Inc. (CSTL) shares trade at $34.42, up 2.11% on the day, as of October 11, 2026.
Live P/E is share price divided by annual earnings per share. It is blank when earnings are missing, zero, or negative — not a 0× multiple.