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NASDAQ · Health careCastle Biosciences Inc (CSTL)
Castle Biosciences Inc brought in $377.1M of revenue over the twelve months to September 30, 2026, up 9.8% from a year earlier. It posted a net loss of $23M. Operating cash flow minus capital spending left $28.3M of free cash flow in fiscal 2025. At September 30, 2026 it held $78M in cash against $10.1M of debt. Its latest periodic report to the SEC is the quarterly report (10-Q) filed on November 5, 2026.
Key facts about Castle Biosciences Inc
- Net worth
- Castle Biosciences Inc has a market value (market cap) of $1.1B at the latest share price, and shareholders' equity of $478.4M on its balance sheet at September 30, 2026. A company's "net worth" usually means one of these: what the market pays for all its shares, or its assets minus its liabilities.
- Revenue and profit
- In fiscal 2025 revenue was $344.2M (+3.7% year on year), with a net loss of $24.2M. Over the 12 months to September 30, 2026: revenue $377.1M, net loss $23M.
- Cash flow
- In fiscal 2025 operations brought in $64.3M of cash; after $36M of capital spending, free cash flow was $28.3M.
- Latest report
- The latest periodic report (quarterly report, 10-Q) was filed with the SEC on November 5, 2026 and covers the period to September 30, 2026. Open on SEC EDGAR
- Next earnings report
- Castle Biosciences Inc's next report is expected around January 12, 2027. That is an estimate from its filing rhythm, not a date the company has announced.
What Castle Biosciences Inc does
Castle Biosciences Inc is registered with the SEC under industry code SIC 8071 (Services-Medical Laboratories). Its shares trade on NASDAQ under the ticker CSTL.
Revenue and profit by year
Key figures
| Fiscal year | Revenue | Net income | Diluted EPS | Free cash flow |
|---|---|---|---|---|
| 2025 | $344.2M | -$24.2M | -$0.83 | $28.3M |
| 2024 | $332.1M | $18.2M | $0.62 | $36.5M |
| 2023 | $219.8M | -$57.5M | -$2.14 | -$19.2M |
| 2022 | $137M | -$67.1M | -$2.58 | -$47.3M |
| 2021 | $94.1M | -$31.3M | -$1.24 | -$22.5M |
| 2020 | $62.6M | -$10.3M | -$0.54 | $5.1M |
Earnings: every quarter and the next report date
Full financial statements: income, balance sheet and cash flow
Where CSTL ranks in Health care
Latest SEC filings
What Castle Biosciences Inc has filed recently, newest first. Each links to the original document on SEC EDGAR.
- November 5, 2026Quarterly report 10-Q · period to September 30, 2026Revenue rose 24% to $102.9M versus the same quarter last year; diluted EPS -$0.13 versus -$0.02.
- November 5, 2026
- October 29, 2026Passive stake changed SCHEDULE 13G/A
- July 30, 2026Quarterly report 10-Q · period to June 30, 2026Revenue rose 20% to $103.5M versus the same quarter last year; diluted EPS -$0.07 versus $0.15.
- July 30, 2026
- May 29, 2026
- May 15, 2026Passive stake changed SCHEDULE 13G/A
- May 15, 2026Passive stake changed SCHEDULE 13G/A
- May 6, 2026Quarterly report 10-Q · period to March 31, 2026Revenue fell 4.9% to $83.7M versus the same quarter last year; diluted EPS -$0.49 versus -$0.90.
- May 6, 2026
What is CSTL worth? A DCF from its reported cash flow
Insider trades
What the people running Castle Biosciences Inc did with its shares, from the Form 4 filings they must send the SEC within two business days.
Insiders sold $6.5M worth of shares in the last 90 days and bought none on the open market. Most of the selling (76%) was pre-planned under Rule 10b5-1 trading plans.
| Date | Insider | What | Shares | Value |
|---|---|---|---|---|
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1) | 7,555 | $272K |
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1), indirect | 2,816 | $101.4K |
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1), indirect | 2,393 | $86.2K |
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1) | 1,025 | $37.7K |
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1), indirect | 382 | $14.1K |
| November 2, 2026 | Maetzold Derek JPres. & Chief Exec. Officer, Director | Soldpre-planned (10b5-1), indirect | 325 | $12K |
| October 28, 2026 | Juvenal Tobin WChief Commercial Officer | Soldpre-planned (10b5-1) | 1,237 | $44K |
| October 28, 2026 | Juvenal Tobin WChief Commercial Officer | Soldpre-planned (10b5-1) | 5,341 | $195.6K |
Who owns CSTL
Three views from three kinds of SEC filings, each with its own date. They overlap and are not added up.
5% holders
| Holder | Of class | Filed |
|---|---|---|
| RTW Investments, LP13G, passive with 1 related filers | 9.3% | May 15, 2026 |
Largest institutional holders
Positions that investment managers reported on Form 13F for the quarter ended June 30, 2026, largest first, with the change on the quarter ended March 31, 2026. Managers file 13F up to 45 days after a quarter ends. 176 managers reported a position.
| Holder | Shares | Change on quarter |
|---|---|---|
| BlackRock, Inc. | 3,291,963 | +309,017 |
| Rtw Investments, LP | 2,778,335 | +20,000 |
| Principal Financial Group Inc | 1,726,648 | -43,229 |
| Vanguard Capital Management LLC | 1,226,497 | +48,975 |
| Vanguard Portfolio Management LLC | 840,785 | -20,986 |
| Allianz Asset Management GmbH | 811,324 | 0 |
| Summit Partners Public Asset Management, LLC | 824,872 | -115,813 |
| State Street Corp | 822,079 | +53,000 |
| Geode Capital Management, LLC | 795,912 | +67,812 |
| Mackenzie Financial Corp | 793,507 | +719,396 |
| Dimensional Fund Advisors LP | 791,085 | -248,676 |
| Jefferies Financial Group Inc. | 647,391 | new |
| Qube Research & Technologies Ltd | 589,300 | +29,717 |
| AIGH Capital Management LLC | 545,101 | -45,500 |
| Renaissance Technologies LLC | 371,200 | -161,600 |
| Goldman Sachs Group Inc | 358,397 | +17,226 |
| Point72 Asset Management, L.P. | 357,317 | new |
| Kennedy Capital Management LLC | 348,371 | new |
| Connor, Clark & Lunn Investment Management Ltd. | 331,727 | -45,355 |
| Morgan Stanley | 329,684 | -99,250 |
Insiders
11 insiders reported holding 405,895 shares in total, about $14M at the last price.
| Holder | Shares |
|---|---|
| Oelschlager Kristen MChief Operating Officer | 86,00572,649 held indirectly |
| Goldberg EllenDirector | 40,921 |
| Olson TiffanyDirector | 39,573 |
| Juvenal Tobin WChief Commercial Officer | 38,853 |
| Caple KimDirector | 36,121 |
| Harrison MilesDirector | 35,631 |
| Stokes FrankChief Financial Officer | 35,177 |
| Cotton RodneyDirector | 32,998 |
| Cole G BradleyDirector | 32,976 |
| Bradbury DanielDirector | 22,340 |
Questions about CSTL
What does Castle Biosciences Inc do?
Castle Biosciences Inc is a company in the Health care sector, listed on NASDAQ as CSTL. Its shares trade on NASDAQ under the ticker CSTL.
What is Castle Biosciences Inc's net worth?
Castle Biosciences Inc has a market value (market cap) of $1.1B at the latest share price, and shareholders' equity of $478.4M on its balance sheet at September 30, 2026. A company's "net worth" usually means one of these: what the market pays for all its shares, or its assets minus its liabilities.
Is Castle Biosciences Inc profitable?
No. Over the twelve months to September 30, 2026 it reported a net loss of $23M on revenue of $377.1M.
How much revenue does Castle Biosciences Inc make?
Over the twelve months to September 30, 2026 Castle Biosciences Inc reported revenue of $377.1M. That is 9.8% more than a year earlier.
When did Castle Biosciences Inc last report?
Its most recent periodic report is the quarterly report (10-Q) filed on November 5, 2026. It covers the period to September 30, 2026. Its newest filing of any kind is the planned insider sale from November 9, 2026.
When is Castle Biosciences Inc's next earnings report?
Castle Biosciences Inc's next report is expected around January 12, 2027. That is an estimate from its filing rhythm, not a date the company has announced.
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Where the numbers come from
Financial figures are the values Castle Biosciences Inc tagged in its own SEC filings (XBRL), taken from the latest filing for each period, so restatements replace older figures. Revenue, profit and cash flow are for full fiscal years unless marked as the last twelve months, which is the sum of the four most recent quarters. Where a company reports only the full year, the fourth quarter is the year minus the first three.
Prices are delayed end-of-day market data in the listing currency, and market cap moves with the price. P/E is shown only when earnings per share are positive. Nothing here is investment advice.