CSTL at a glance
CASTLE BIOSCIENCES INC (CSTL, SEC CIK 1447362) filed its latest 10-K annual report on February 26, 2026, a 10-Q quarterly report on July 30, 2026, an 8-K current report on July 30, 2026 and Form 4 insider filings as recently as October 5, 2026. SignalX summarizes each filing with AI and tracks the company's insider trades and institutional holders.
- For the fiscal year ended December 31, 2025 (FY2025), CASTLE BIOSCIENCES INC (CSTL) reported revenue of $344.2 million (up 3.7% from FY2024) and a net loss of $24.2 million. Diluted EPS was -$0.83.
- As of June 30, 2026, 28 institutional investment managers tracked by SignalX reported holding CASTLE BIOSCIENCES INC (CSTL) shares worth $274.8 million in 13F-HR filings.
- The most recent insider open-market sale reported on Form 4 was by Oelschlager Kristen M on October 1, 2026 of 2,807 shares at $35.75 per share.
- In the last 90 days, CSTL insiders reported 0 open-market purchases ($0) and 88 open-market sales ($7.8M) on Form 4, a net sale of $7.8M.
Source: SEC EDGAR (XBRL financial data, 13F-HR and Form 4 filings).
- Revenue · FY2025
- $344.2M
- +3.7% vs prior year
- Insiders · 90 days
- 0 buys · 88 sells
- Net −$7.8M
- 13F holders
- 28 funds
- $274.8M · +1 vs prior quarter
- Latest 8-K
- Jul 30, 2026
- Item 2.02 · Item 7.01
AI 10-Q Quarterly Report Analysis
Latest 10-Q, quarter ended Jun 30, 2026
Management Discussion & Analysis
- Test reports 30,822, up 16% YoY, driven by TissueCypher volume growth of 63%
- TissueCypher strongest line, 14,988 reports versus DecisionDx-UM’s 482
- AdvanceAD-Tx generated approximately 1,000 orders during limited access launch
- Pittsburgh laboratory expansion supporting TissueCypher capacity and future growth
- Phased AdvanceAD-Tx availability planned throughout remainder of 2026 amid macroeconomic uncertainties
Risk Factors
- Newly heightened geopolitical risk: U.S.-Iran conflict since February 2026, with Strait of Hormuz closure risk threatening energy and shipping continuity
- Most material reimbursement update: DecisionDx-SCC became noncovered under Novitas’ LCD effective April 24, 2025
- Regulatory risk: DecisionDx-SCC reconsideration remains pending, with MolDX placing the test on a waiting list
- Near-term revenue concentration: Majority expected from DecisionDx-Melanoma and TissueCypher as DecisionDx-SCC revenue declines in 2026
- Financial risk: Six-month net loss reached $16.6 million, increasing accumulated deficit to $240.9 million
AI summary of the CSTL 10-Q filed . Generated from the filing text; verify against the original.View on SEC EDGAR10-K vs 10-Q vs 8-K
AI 8-K Current Report Analysis
The most recent material events, by 8-K item
Item 2.02: Results of Operations and Financial Condition
- Q2 2026 results for quarter ended June 30, 2026 released July 30, 2026
- Detailed financial results and management commentary contained in Exhibit 99.1
Item EX-99.1: Item EX-99.1
- Q2 revenue $103.5M, up from $86.2M, with core test reports up 32%
- TissueCypher reports surged to 14,988 from 9,170, offsetting modest DecisionDx-Melanoma growth
Item 7.01: Regulation FD Disclosure
- Exhibit 99.2 provides investor presentation materials for management’s future meetings
- Presentation may contain updated company strategy, operating information, or business outlook relevant to valuation
Item 5.07: Submission of Matters to a Vote of Security Holders
- Stockholders elected Ellen Goldberg, Miles D. Harrison, and Tiffany P. Olson as Class I directors through 2029
- Director support varied, with Tiffany P. Olson receiving 14,380,655 votes for versus 8,192,776 withheld
Item 2.02: Results of Operations and Financial Condition
- Q1 2026 results for quarter ended March 31, 2026 released May 6, 2026
- Detailed financial results and management commentary contained in Exhibit 99.1
Item 7.01: Regulation FD Disclosure
- Castle Biosciences released investor presentation materials on May 6, 2026
- Presentation may guide management discussions in future investor meetings
AI summaries of CSTL 8-K current reports filed with the SEC. What 8-K item codes mean
SignalX for CSTL
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Recent Insider Transactions (Form 4)
Latest reported trades by officers, directors and 10% owners
| Insider | Type | Date | Shares | Price |
|---|---|---|---|---|
| Oelschlager Kristen M | Sell | Oct 1, 2026 | 2,807 | $35.75 |
| Oelschlager Kristen M | M | Oct 1, 2026 | 4,153 | $3.38 |
| Oelschlager Kristen M | Sell | Oct 1, 2026 | 1,346 | $36.38 |
| Oelschlager Kristen M | M | Oct 1, 2026 | 4,153 | - |
| Juvenal Tobin W | Sell | Sep 30, 2026 | 1,034 | $34.20 |
| Juvenal Tobin W | Sell | Sep 29, 2026 | 5,543 | $35.50 |
| MAETZOLD DEREK J | M | Sep 21, 2026 | 8,580 | - |
| MAETZOLD DEREK J | Sell | Sep 21, 2026 | 8,580 | $35.33 |
Financial SummaryXBRL
| Metric | FY2023 | FY2024 | FY2025 |
|---|---|---|---|
| Profitability | |||
| Revenue | - | $332.1M | $344.2M |
| Operating Income | - | $8.7M | -$42.8M |
| Net Income | -$57.5M | $18.2M | -$24.2M |
| Op. Margin | - | 2.6% | -12.4% |
| Net Margin | - | 5.5% | -7.0% |
| Balance Sheet | |||
| Total Assets | - | $531.2M | $578.6M |
| Equity | $391.3M | $455.8M | $470.9M |
| ROE | -14.7% | 4.0% | -5.1% |
| Per Share | |||
| EPS | $-2.14 | $0.62 | $-0.83 |
| Cash Flow | |||
| Operating CF | -$5.6M | $64.9M | $64.3M |
| CapEx | - | $28.3M | $36.0M |
Source: XBRL data in CASTLE BIOSCIENCES INC (CSTL)'s 10-K filings on SEC EDGAR, in USD. Compare across companies →
13F Fund Holdings: Quarterly Trend
Latest: Q2 2026Aggregate CSTL share value held by 13F filers tracked by SignalX, by quarter.
Quarterly totals table
| Quarter | Funds | Total value |
|---|---|---|
| Q2 2026 | 28 | $274.8M |
| Q1 2026 | 27 | $287.2M |
| Q4 2025 | 27 | $468.6M |
| Q3 2025 | 27 | $292.2M |
| Q2 2025 | 27 | $270.9M |
| Q1 2025 | 24 | $175.6M |
| Q4 2024 | 18 | $214.1M |
| Q3 2024 | 15 | $149.8M |
- BlackRock+309.0K (+10%)
- Citadel Advisors LLC+144.4K (+119%)
- AQR Capital Management+101.7K (+157%)
- State Street Corp+53.0K (+7%)
- Vanguard Capital Management LLC+49.0K (+4%)
- Dimensional Fund Advisors−248.7K (-24%)
- Renaissance Technologies LLC−161.6K (-30%)
- Two Sigma Investments−148.5K (-60%)
- Millennium Management−147.9K (-42%)
- Morgan Stanley−99.3K (-23%)
- Allstate+9.6K
Source: 13F-HR filings on SEC EDGAR (aggregated from 193 fund-quarter rows). Reflects only 13F filers tracked by SignalX, not the full institutional ownership universe. How 13F filings work
CSTL filing archive
AI analysis pages for each 10-K, 10-Q and 8-K
10-Q quarterly reports
8-K current reports
Latest 2026 SEC Filings: 10-K, 10-Q, 8-K & Form 4
| Form | Filing date | Period | Analysis | SEC |
|---|---|---|---|---|
| 4 | Oct 5, 2026 | - | - | - |
| 4 | Oct 1, 2026 | - | - | - |
| 4 | Sep 23, 2026 | - | - | - |
| 4 | Sep 16, 2026 | - | - | - |
| 4 | Sep 15, 2026 | - | - | - |
| 4 | Sep 3, 2026 | - | - | - |
| 4 | Sep 2, 2026 | - | - | - |
| 4 | Sep 1, 2026 | - | - | - |
| 4 | Aug 27, 2026 | - | - | - |
| 4 | Aug 26, 2026 | - | - | - |
| 4 | Aug 19, 2026 | - | - | - |
| 4 | Aug 18, 2026 | - | - | - |
| 4 | Aug 18, 2026 | - | - | - |
| 4 | Aug 6, 2026 | - | - | - |
| 4 | Aug 6, 2026 | - | - | - |
| 4 | Aug 5, 2026 | - | - | - |
| 4 | Aug 4, 2026 | - | - | - |
| 4 | Aug 4, 2026 | - | - | - |
| 10-Q | Jul 30, 2026 | Jun 30, 2026 | Analysis | |
| 8-K | Jul 30, 2026 | - | Analysis | - |
| 4 | Jul 29, 2026 | - | - | - |
| 4 | Jul 16, 2026 | - | - | - |
| 4 | Jul 6, 2026 | - | - | - |
| 4 | Jul 6, 2026 | - | - | - |
| 4 | Jun 18, 2026 | - | - | - |
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CSTL SEC filings: frequently asked questions
Are CSTL insiders buying or selling?
In the last 90 days, CASTLE BIOSCIENCES INC (CSTL) officers, directors and 10% owners reported no open-market purchases and 88 open-market sales worth $7.8 million by 4 insiders on Form 4. Many insider sales are pre-planned or for taxes, so purchases usually carry more information.
Which institutions hold CSTL stock?
As of June 30, 2026, the largest CASTLE BIOSCIENCES INC (CSTL) holders among the 13F filers tracked by SignalX were BlackRock ($78.5 million), Principal Financial Group ($41.2 million), Vanguard Capital Management LLC ($29.3 million), Vanguard Portfolio Management LLC ($20.1 million), State Street Corp ($19.6 million). 13F-HR reports are filed up to 45 days after each quarter ends.
What was CSTL's revenue in fiscal year 2025?
For the fiscal year ended December 31, 2025 (FY2025), CASTLE BIOSCIENCES INC (CSTL) reported revenue of $344.2 million (up 3.7% from FY2024) and a net loss of $24.2 million. Diluted EPS was -$0.83. The figures come from the XBRL data in the 10-K.
What did CSTL report in its latest 8-K?
CASTLE BIOSCIENCES INC (CSTL) filed an 8-K on July 30, 2026 reporting Item 2.02 (Results of Operations and Financial Condition) and Item 7.01 (Regulation FD Disclosure). Q2 2026 results for quarter ended June 30, 2026 released July 30, 2026.
What are the latest CSTL SEC filings?
CASTLE BIOSCIENCES INC (CSTL) filed its latest 10-K annual report on February 26, 2026, a 10-Q quarterly report on July 30, 2026, an 8-K current report on July 30, 2026 and a Form 4 insider filing on October 5, 2026.
What is CSTL's SEC CIK number?
CASTLE BIOSCIENCES INC (CSTL)'s SEC Central Index Key (CIK) is 1447362. EDGAR lists every CSTL filing under that number.
Ask anything about CSTL
The research agent reads CSTL's filings, financials, insider trades and 13F holders, then answers with sources.