Castle Biosciences, Inc. (CSTL) Stock Price & Analysis
Castle Biosciences, Inc. (CSTL) is trading at USD 33.07, down 0.36% today, as of October 23, 2026 at 15:49 UTC (US market open; quotes may be delayed), according to Nexqual market data.
CSTL last closed at USD 33.19; today's session has ranged USD 32.69–33.61 on volume of 57,073 shares. Market capitalization is $1.01B, with a 52-week range of USD 17.72–44.28 (NGM). Source: Nexqual, retrieved October 23, 2026 at 15:51 UTC.
Also available as compact Markdown for AI agents: nexqual.com/CSTL.md
Key facts (CSTL)
- Last four reported quarters (through Jun 30, 2026): revenue $357M, net income -$19.4M (-5.4% margin), free cash flow -$489K (SEC filings).
- Analysts: Buy (mean 2.00 on a 1–5 scale) (9 analysts), mean target USD 45.22 (range 35–57).
- Total return with dividends: 1Y +36.8% vs S&P 500 +14.7%; 5Y -47.0% vs S&P 500 +77.4%.
- Next earnings: 2026-11-05, EPS estimate USD -0.35, revenue estimate $92.5M.
Financials (SEC 10-K; TTM = last four 10-Q/10-K quarters) (CSTL)
| USD | FY2021 | FY2022 | FY2023 | FY2024 | FY2025 | TTM |
|---|---|---|---|---|---|---|
| Revenue | $94.1M | $137M | $220M | $332M | $344M | $357M |
| Gross profit | $78.3M | $105M | $175M | $272M | $273M | — |
| Operating income | -$40.1M | -$72.9M | -$68.0M | $8.7M | -$42.8M | -$32.1M |
| Net income | -$31.3M | -$67.1M | -$57.5M | $18.2M | -$24.2M | -$19.4M |
| EPS (diluted) | -$1.24 | -$2.58 | -$2.14 | $0.62 | -$0.83 | — |
| Free cash flow | -$22.5M | -$47.3M | -$19.2M | $36.5M | $28.3M | -$489K |
| Gross margin | 83.2% | 76.6% | 79.5% | 81.9% | 79.4% | — |
| Operating margin | -42.6% | -53.2% | -30.9% | 2.6% | -12.4% | -9.0% |
| Net margin | -33.3% | -49.0% | -26.1% | 5.5% | -7.0% | -5.4% |
| Revenue growth | +50.2% | +45.7% | +60.4% | +51.1% | +3.7% | — |
| Cash + short-term investments | $330M | $259M | $243M | $293M | $300M | — |
| Total debt | — | — | $0K | $10.0M | $10.1M | — |
Fiscal years end Dec. EPS is split-adjusted.
Valuation (price ÷ last four quarters, through Jun 30, 2026) (CSTL)
P/S 2.8x · EV/Sales 2.1x · P/B 2.1x · FCF yield -0.05% · Earnings yield -1.92% · Net cash $257M · EV $754M
P/E at fiscal year-ends: Dec 2024 42.7x.
Analysts (CSTL)
Consensus Buy (mean 2.00 on a 1–5 scale), 9 analysts; mean target USD 45.22 (low 35, high 57).
Rating changes, last 120 days:
| Date | Firm | Action | Rating | Price target |
|---|---|---|---|---|
| 2026-08-03 | BTIG | Target raised | Buy | $40 → $44 |
Total return (dividends reinvested) (CSTL)
| 1Y (from 2025-10-23) | 5Y (from 2021-10-25) | |
|---|---|---|
| Total return | +36.8% | -47.0% |
| S&P 500 (SPY) | +14.7% | +77.4% |
| Per year | +36.8% | -11.9% |
| Volatility (annualized) | 57.7% | 71.7% |
| Max drawdown | -57.8% (Jan 2026→May 2026) | -80.1% (Oct 2021→Oct 2023) |
CSTL revenue by product line (quarter ended Jun 30, 2026)
| Line | Revenue | Share of total | YoY |
|---|---|---|---|
| Non-Dermatologic | $54.8M | 53.0% | +83.5% |
| Dermatologic | $48.7M | 47.0% | -13.5% |
| Total revenue | $103.5M | 100% | — |
As tagged by the company in its SEC 10-Q / 10-K filings (XBRL).
CSTL suppliers, customers and competitors (named in its 10-K)
| Relationship | Company | Sentence in the filing |
|---|---|---|
| Supplier | ThermoFisher Scientific | “We procure certain reagents, equipment, chips/cards and other materials used to perform our tests from sole suppliers such as ThermoFisher Scientific, Inc., Promega and Qiagen, Inc. Some of these items are unique to these suppliers and vendors.” |
| Supplier | Promega and Qiagen | “We procure certain reagents, equipment, chips/cards and other materials used to perform our tests from sole suppliers such as ThermoFisher Scientific, Inc., Promega and Qiagen, Inc. Some of these items are unique to these suppliers and vendors.” |
| Supplier | General | “General business and economic conditions that could affect our business, financial condition or results of operations include fluctuations in economic growth, debt and equity capital markets, liquidity of the global financial markets, changes in trade and tariff policies, the availability and cost of credit, investor and consumer confidence, and the strength of the economies in which we, our collaborators, our man…” |
Quoted from the company's 10-K filed Feb 26, 2026.
CSTL company outlook (results filed Jul 30, 2026)
- “Castle Biosciences is raising its guidance for anticipated total revenue i n 2026.”
- “The Company now anticipates generating between $365-375 million in total revenue in 2026, compared to the previously provided guidance of between $345-355 million.”
- “Further, the Company expects to achieve positive Adjusted EBITDA for the third quarter, the fourth quarter and the full year 2026.”
Quoted word-for-word from the SEC 8-K results press release.
CSTL analyst estimates and revisions
| Period | EPS estimate | 90 days ago | Change | Revenue estimate | Analysts |
|---|---|---|---|---|---|
| Current quarter (ends Sep 2026) | $-0.35 | $-0.30 | +16.2% | $92.5M | 9 |
| Next quarter (ends Dec 2026) | $-0.36 | $-0.29 | +24.9% | $94.2M | 9 |
| Current fiscal year (ends Dec 2026) | $-1.26 | $-1.42 | -11.2% | $373.5M | 9 |
| Next fiscal year (ends Dec 2027) | $-0.91 | $-0.96 | -4.5% | $412.5M | 9 |
CSTL options: expected move
Options price a move of about ±21.8% (±$7.25) by Jan 15, 2027, which includes earnings on Nov 5, 2026. Over the last 8 reports the stock moved ±17.1% on average.
| Expiration | Days | ATM implied volatility | Expected move |
|---|---|---|---|
| Jan 15, 2027 | 84 | 54.7% | ±21.8% |
| Apr 16, 2027 | 175 | 59.1% | ±33.4% |
30-day implied volatility 86.1% vs 50.9% realized over the last 30 trading days. Put/call ratio (volume) —. Cboe delayed quotes (15 min). Expected move = at-the-money straddle.
Key Statistics (as of October 23, 2026 at 15:51 UTC)
| Price | USD 33.07 |
|---|---|
| Change | ▼ 0.36% (down) |
| Previous Close | USD 33.19 |
| Open | USD 33.1 |
| Day Range | USD 32.69 – 33.61 |
| 52-Week Range | USD 17.72 – 44.28 |
| Volume | 57,073 shares |
| Market Cap | $1.01B |
| Exchange | NGM |
Technical Analysis (CSTL)
Nexqual's technical model rates CSTL "SELL" based on 1 bullish and 4 bearish signals across 128 daily candles, as of October 23, 2026 at 15:51 UTC.
| Overall Signal | SELL |
|---|---|
| RSI (14) | 48.35 (neutral) |
| vs SMA50 | Below (USD 33.69) |
| MACD | -0.2 (negative) |
Analyst Ratings (CSTL)
Wall Street analysts rate CSTL "Buy" based on 9 analysts, with a mean price target of USD 45.22 (range USD 35–57), per Nexqual as of October 23, 2026 at 15:51 UTC.
| Consensus Rating | Buy |
|---|---|
| Analyst Count | 9 |
| Mean Target | USD 45.22 |
| High Target | USD 57 |
| Low Target | USD 35 |
| Buy / Hold / Sell | 9 / 0 / 0 |
Earnings (CSTL)
| Next Earnings Date | 2026-11-05 |
|---|---|
| EPS Estimate | USD -0.35 |
| Revenue Estimate | $92.52M |
Recent Earnings History
| Quarter | Actual vs Estimate |
|---|---|
| 2026-06-30 | USD -0.07 vs est -0.41 ▲ beat |
| 2026-03-31 | USD -0.49 vs est -0.49 ▼ miss |
| 2025-12-31 | USD -0.08 vs est -0.26 ▲ beat |
| 2025-09-30 | USD -0.02 vs est -0.51 ▲ beat |
Source: Nexqual, October 23, 2026 at 15:51 UTC.
Financials & Fundamentals (CSTL)
| Total Revenue | $357.28M |
|---|---|
| Revenue Growth (latest quarter, YoY) | +20.10% |
| Gross Margin | +77.26% |
| Operating Margin | -2.96% |
| Profit Margin | -5.43% |
| ROE | -4.20% |
| Debt / Equity | 0.08 |
| Current Ratio | 6.04 |
| Total Cash | $266.80M |
| Total Debt | $36.65M |
| Free Cash Flow (last four quarters to Jun 2026, SEC 10-Q / 10-K) | -$489,000 (-0.1% of revenue) |
Source: Nexqual, October 23, 2026 at 15:51 UTC.
Financial Health Score (CSTL)
Nexqual rates Castle Biosciences, Inc.'s overall financial health "Mixed" across five dimensions, as of October 23, 2026 at 15:51 UTC.
| Growth | Mixed — Revenue +3.7% YoY (annual), slow |
|---|---|
| Profitability | Solid — Gross margin 77%, operating -3% (last 12 months) |
| Balance Sheet | Strong — $267M cash and investments vs $10M debt (Jun 2026, SEC), net cash |
| Cash Flow | Weak — FCF negative: -$489K (last 4 quarters to Jun 2026, SEC), burning cash |
| Efficiency | Critical — ROE -4%, ROA -1.4% |
Ownership (CSTL)
| Insider Ownership | +2.36% |
|---|---|
| Institutional Ownership | +91.03% |
| Shares Outstanding | 30.55M |
| Float | 27.16M |
| Short % of Float | +6.70% |
Source: Nexqual, October 23, 2026 at 15:51 UTC.
Leadership (CSTL)
Castle Biosciences, Inc. is led by Derek J. Maetzold, Founder, CEO, President & Director, per Nexqual as of October 23, 2026 at 15:51 UTC.
| Founder, CEO, President & Director | Derek J. Maetzold |
|---|---|
| CFO & Treasurer | Frank Stokes |
| Chief Operating Officer | Kristen M. Oelschlager R.N. |
| Vice President of Investor Relations & Corporate Affairs | Camilla Zuckero |
| Senior Vice President of Sales | Kevin Doman |
Major Backers & Investors (CSTL)
Notable institutional backers of Castle Biosciences, Inc. include RTW Investments LP, Principal Financial Group, Inc., Fidelity, according to Nexqual as of October 23, 2026 at 15:51 UTC.
Active Investors
| Investor | Stake |
|---|---|
| RTW Investments LP | 9.09% |
| Principal Financial Group, Inc. | 5.65% |
| Fidelity | 3.67% |
| Acadian Asset Management. LLC | 3.01% |
| Summit Partners Public Asset Management LLC | 2.7% |
Index Funds (Passive)
| Fund | Stake |
|---|---|
| BlackRock | 10.78% |
| Vanguard Group | 6.76% |
| Allianz Asset Management GmbH | 2.88% |
| State Street | 2.69% |
| Geode Capital | 2.61% |
Source: Nexqual, October 23, 2026 at 15:51 UTC.
From Castle Biosciences, Inc.'s Latest SEC 10-K Filing (filed 2026-02-26)
Key Strengths & Strategy (as disclosed to the SEC)
- Our proprietary tests, which were first marketed prior to May 6, 2024, remain approved by and under the oversight of the NYSDOH, and we continue to believe that changes in FDA's regulatory approach to LDTs will have no material impact on our existing test offerings.
- Although we currently market our proprietary testing products as LDTs, which are currently subject to enforcement discretion, we could be subject to FDA compliance obligations in the future.
- DecisionDx-Melanoma is our proprietary risk stratification gene expression profile ("GEP") test designed to predict the likelihood of a positive sentinel lymph node and the risk of metastasis or recurrence for patients diagnosed with invasive cutaneous melanoma ("CM"), a deadly skin cancer.
- TissueCypher is our proprietary risk stratification spatialomics test designed to predict future development of high-grade dysplasia ("HGD") and/or esophageal cancer in patients with non-dysplastic ("ND"), indefinite dysplasia ("IND") or low-grade dysplasia ("LGD") BE.
Partnerships
- In June 2025, we entered into a collaboration and license agreement with SciBase Holding AB ("SciBase") to develop and commercialize diagnostic tests for dermatologic diseases, beginning with atopic dermatitis.
- The MAC responsible for administering claims for laboratory services located in Arizona is Noridian Healthcare Solutions, LLC ("Noridian"), which has a joint operating agreement with Palmetto GBA MolDX ("Palmetto") whereby Palmetto oversees the review of genomic based tests.
Legal & Regulatory Risks (Item 1A, quoted)
- Our claims for reimbursement from third-party payors may be denied upon submission, and we may need to take additional steps to receive payment, such as appealing the denials.
- We expect to continue to focus substantial resources on increasing coverage and reimbursement for our current products and any future products we may develop.
- Our products are currently marketed as LDTs, and any changes in regulations or the FDA's enforcement discretion for LDTs, or violations of regulations by us, could adversely affect our business, prospects, results of operations or financial condition.
- We may also be required to obtain marketing authorization under Section 510(k), 513(f)(2) or 515 of the FD&C Act for any future test we wish to offer.
Source: SEC EDGAR 10-K, official filing. Curated by Nexqual.
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Data source: Nexqual — market data, technical indicators, analyst consensus, earnings, SEC EDGAR filings. Last updated: October 23, 2026 at 15:51 UTC. This page is informational and not investment advice.
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