Castle Biosciences Inc
CSTL Nasdaq Services-Medical Laboratories Financials FY2018–FY2025
Revenue
Total sales reported in the income statement.
$344M
3.7%
vs prior year
Operating margin
Operating income as a share of revenue.
−12.4%
15.0 pts
Net income
Profit after all expenses, interest and tax.
−$24.2M
232.4%
Free cash flow
Cash from operations minus capital spending.
$28.3M
22.5%
Return on capital
After-tax operating income as a share of the money invested in the business: debt plus equity, minus cash.
−18.6%
22.6 pts
Market cap
Last close times the latest diluted share count, so it is approximate.
—
P/E
Last close divided by diluted earnings per share over the last four quarters.
—
On −$0.64 EPS (TTM)
What Castle Biosciences Inc does
No business description yet.
- Legal name
- CASTLE BIOSCIENCES INC
- Fiscal year ends
- December 31, 2025
- Latest annual report
- 10-K · Feb 26, 2026
- Accession · CIK
- 0001628280-26-012272
0001447362
Revenue and margins
Castle Biosciences Inc had $344M of revenue in fiscal 2025, up 3.7% on the year before.
FY18
Revenue $22.8M
FY19
Revenue $51.9M
FY20
Revenue $62.6M
FY21
Revenue $94.1M
FY22
Revenue $137M
FY23
Revenue $220M
FY24
Revenue $332M
FY25
Revenue $344M
Q3 '23
Revenue $61.5M
Q4 '23
Revenue $66.1M
Q1 '24
Revenue $73.0M
Q2 '24
Revenue $87.0M
Q3 '24
Revenue $85.8M
Q4 '24
Revenue $86.3M
Q1 '25
Revenue $88.0M
Q2 '25
Revenue $86.2M
Q3 '25
Revenue $83.0M
Q4 '25
Revenue $87.0M
Q1 '26
Revenue $83.7M
Q2 '26
Revenue $104M
FY18
Gross 76.8%
Operating −16.8%
Net −27.9%
FCF −55.2%
FY19
Gross 85.9%
Operating 14.1%
Net 10.2%
FCF 11.7%
FY20
Gross 84.5%
Operating −10.4%
Net −16.4%
FCF 8.2%
FY21
Gross 83.2%
Operating −42.6%
Net −33.3%
FCF −23.9%
FY22
Gross 76.6%
Operating −53.2%
Net −49.0%
FCF −34.5%
FY23
Gross 79.5%
Operating −30.9%
Net −26.1%
FCF −8.8%
FY24
Gross 81.9%
Operating 2.6%
Net 5.5%
FCF 11.0%
FY25
Gross 79.4%
Operating −12.4%
Net −7.0%
FCF 8.2%
Gross
Operating
Net
FCF
Q3 '23
Gross 81.6%
Operating −15.7%
Net −11.2%
FCF 4.2%
Q4 '23
Gross 81.2%
Operating −8.6%
Net −3.9%
FCF 22.4%
Q1 '24
Gross 81.0%
Operating −7.5%
Net −3.5%
FCF −21.9%
Q2 '24
Gross 83.3%
Operating 5.8%
Net 10.3%
FCF 21.6%
Q3 '24
Gross 81.8%
Operating 5.9%
Net 2.6%
FCF 19.8%
Q4 '24
Gross 81.3%
Operating 4.7%
Net 11.1%
FCF 19.5%
Q1 '25
Gross 81.4%
Operating −31.7%
Net −29.4%
FCF −12.2%
Q2 '25
Gross 79.5%
Operating −4.9%
Net 5.2%
FCF 13.4%
Q3 '25
Gross 77.5%
Operating −8.2%
Net −0.6%
FCF 9.4%
Q4 '25
Gross 79.0%
Operating −4.4%
Net −2.7%
FCF 22.7%
Q1 '26
Gross 75.5%
Operating −22.0%
Net −17.4%
FCF −41.3%
Q2 '26
Gross 77.1%
Operating −3.0%
Net −2.0%
FCF 6.3%
Gross
Operating
Net
FCF
Net income and earnings per share
Loss periods are shown in red.
FY18
Net income −$6.4M
FY19
Net income $5.3M
FY20
Net income −$10.3M
FY21
Net income −$31.3M
FY22
Net income −$67.1M
FY23
Net income −$57.5M
FY24
Net income $18.2M
FY25
Net income −$24.2M
Q3 '23
Net income −$6.9M
Q4 '23
Net income −$2.6M
Q1 '24
Net income −$2.5M
Q2 '24
Net income $8.9M
Q3 '24
Net income $2.3M
Q4 '24
Net income $9.6M
Q1 '25
Net income −$25.8M
Q2 '25
Net income $4.5M
Q3 '25
Net income −$0.5M
Q4 '25
Net income −$2.3M
Q1 '26
Net income −$14.5M
Q2 '26
Net income −$2.1M
FY18
Diluted EPS −$5.33
FY19
Diluted EPS −$0.21
FY20
Diluted EPS −$0.54
FY21
Diluted EPS −$1.24
FY22
Diluted EPS −$2.58
FY23
Diluted EPS −$2.14
FY24
Diluted EPS $0.62
FY25
Diluted EPS −$0.83
Q3 '23
Diluted EPS −$0.26
Q4 '23
Diluted EPS −$0.08
Q1 '24
Diluted EPS −$0.09
Q2 '24
Diluted EPS $0.31
Q3 '24
Diluted EPS $0.08
Q4 '24
Diluted EPS $0.32
Q1 '25
Diluted EPS −$0.90
Q2 '25
Diluted EPS $0.15
Q3 '25
Diluted EPS −$0.02
Q4 '25
Diluted EPS −$0.06
Q1 '26
Diluted EPS −$0.49
Q2 '26
Diluted EPS −$0.07
Returns on capital
After-tax operating income as a share of the money invested in the business: debt plus equity, minus cash.
FY18
Return on capital —
Return on equity —
Return on assets −28.4%
FY19
Return on capital 44.7%
Return on equity 37.0%
Return on assets 7.4%
FY20
Return on capital −88.5%
Return on equity −4.1%
Return on assets −3.7%
FY21
Return on capital —
Return on equity −7.6%
Return on assets −6.9%
FY22
Return on capital —
Return on equity −16.6%
Return on assets −14.8%
FY23
Return on capital −36.2%
Return on equity −14.5%
Return on assets −12.8%
FY24
Return on capital 4.0%
Return on equity 4.3%
Return on assets 3.7%
FY25
Return on capital −18.6%
Return on equity −5.2%
Return on assets −4.4%
Return on capital
Return on equity
Return on assets
Cash flow
Free cash flow was $28.3M in fiscal 2025, 8.2% of revenue. Cash from operations minus capital spending.
FY18
Free cash flow −$12.6M
FY19
Free cash flow $6.1M
FY20
Free cash flow $5.1M
FY21
Free cash flow −$22.5M
FY22
Free cash flow −$47.3M
FY23
Free cash flow −$19.2M
FY24
Free cash flow $36.5M
FY25
Free cash flow $28.3M
Q3 '23
Free cash flow $2.6M
Q4 '23
Free cash flow $14.8M
Q1 '24
Free cash flow −$16.0M
Q2 '24
Free cash flow $18.8M
Q3 '24
Free cash flow $17.0M
Q4 '24
Free cash flow $16.8M
Q1 '25
Free cash flow −$10.8M
Q2 '25
Free cash flow $11.6M
Q3 '25
Free cash flow $7.8M
Q4 '25
Free cash flow $19.7M
Q1 '26
Free cash flow −$34.6M
Q2 '26
Free cash flow $6.6M
FY18
Cash from operations −$12.3M
Capital spending $0.3M
FY19
Cash from operations $7.0M
Capital spending $0.9M
FY20
Cash from operations $9.9M
Capital spending $4.8M
FY21
Cash from operations −$19.0M
Capital spending $3.5M
FY22
Cash from operations −$41.7M
Capital spending $5.6M
FY23
Cash from operations −$5.6M
Capital spending $13.6M
FY24
Cash from operations $64.9M
Capital spending $28.3M
FY25
Cash from operations $64.3M
Capital spending $36.0M
Cash from operations
Capital spending
Q3 '23
Cash from operations $5.0M
Capital spending $2.5M
Q4 '23
Cash from operations $18.6M
Capital spending $3.8M
Q1 '24
Cash from operations −$6.8M
Capital spending $9.2M
Q2 '24
Cash from operations $24.0M
Capital spending $5.2M
Q3 '24
Cash from operations $23.3M
Capital spending $6.4M
Q4 '24
Cash from operations $24.4M
Capital spending $7.6M
Q1 '25
Cash from operations −$6.0M
Capital spending $4.7M
Q2 '25
Cash from operations $20.8M
Capital spending $9.3M
Q3 '25
Cash from operations $22.6M
Capital spending $14.8M
Q4 '25
Cash from operations $26.9M
Capital spending $7.2M
Q1 '26
Cash from operations −$22.1M
Capital spending $12.5M
Q2 '26
Cash from operations $15.2M
Capital spending $8.7M
Cash from operations
Capital spending
Dividends, buybacks and share count
Castle Biosciences Inc returned — to shareholders in fiscal 2025. The diluted share count fell 0.9%.
FY18
Dividends —
Buybacks —
FY19
Dividends —
Buybacks —
FY20
Dividends —
Buybacks —
FY21
Dividends —
Buybacks —
FY22
Dividends —
Buybacks —
FY23
Dividends —
Buybacks —
FY24
Dividends —
Buybacks —
FY25
Dividends —
Buybacks —
Dividends
Buybacks
FY18
Diluted shares 0.00B
FY19
Diluted shares 0.01B
FY20
Diluted shares 0.02B
FY21
Diluted shares 0.03B
FY22
Diluted shares 0.03B
FY23
Diluted shares 0.03B
FY24
Diluted shares 0.03B
FY25
Diluted shares 0.03B
Balance sheet
Cash, debt and the ratios that show how comfortably Castle Biosciences Inc can carry it.
FY18
Cash $4.5M
Debt $24.5M
FY19
Cash $98.8M
Debt $26.7M
FY20
Cash $410M
Debt $0.0M
FY21
Cash $330M
Debt —
FY22
Cash $259M
Debt —
FY23
Cash $243M
Debt $0.1M
FY24
Cash $293M
Debt $10.4M
FY25
Cash $300M
Debt $10.5M
Cash
Debt
| Fiscal year end | FY21 | FY22 | FY23 | FY24 | FY25 |
|---|---|---|---|---|---|
| Cash and short-term investments | $330M | $259M | $243M | $293M | $300M |
| Debt incl. finance leases | — | — | $0.1M | $10.4M | $10.5M |
| Net debt / EBITDA | — | — | — | −11.5x | — |
| Debt / equity | — | — | 0.0x | 0.0x | 0.0x |
| Interest coverage | −40,079.0x | −4,285.6x | −6,179.7x | 15.0x | −497.8x |
| Current ratio | 14.2x | 8.1x | 6.2x | 7.3x | 5.3x |
| Quick ratio | 14.1x | 8.0x | 6.0x | 7.1x | 5.1x |
| Total assets | $463M | $447M | $453M | $531M | $579M |
| Total liabilities | $50.8M | $48.2M | $62.1M | $75.4M | $108M |
| Shareholders' equity | $412M | $399M | $391M | $456M | $471M |
| Net debt (− = net cash) | — | — | −$243M | −$283M | −$289M |
Insider trades
Open-market purchases and sales by officers, directors and 10% owners, from Form 4 filings. 'Plan' marks trades under a pre-arranged Rule 10b5-1 plan.
Bought, 12 months
$0.0M
0 insiders
Sold, 12 months
$0.0M
0 insiders
Of sales under plans
—
$0.0M
No open-market insider trades in the last 12 months.
Piotroski F-score
Nine pass/fail tests of profitability, funding and efficiency. 8–9 is strong, 0–2 weak.
| Test | FY18 | FY19 | FY20 | FY21 | FY22 | FY23 | FY24 | FY25 |
|---|---|---|---|---|---|---|---|---|
| Net income is positive | ✕ | ✓ | ✕ | ✕ | ✕ | ✕ | ✓ | ✕ |
| Cash from operations is positive | ✕ | ✓ | ✓ | ✕ | ✕ | ✕ | ✓ | ✓ |
| Return on assets rose | — | ✓ | ✕ | ✕ | ✕ | ✓ | ✓ | ✕ |
| Cash from operations exceeds net income | ✕ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Debt fell relative to assets | — | ✓ | ✓ | — | — | — | ✕ | ✓ |
| Current ratio rose | — | ✓ | ✓ | ✕ | ✕ | ✕ | ✓ | ✕ |
| Share count didn't rise | — | ✕ | ✕ | ✕ | ✕ | ✕ | ✕ | ✓ |
| Gross margin rose | — | ✓ | ✕ | ✕ | ✕ | ✓ | ✓ | ✕ |
| Revenue rose relative to assets | — | ✕ | ✕ | ✓ | ✓ | ✓ | ✓ | ✕ |
| F-score | — / 3 | 7 / 9 | 4 / 9 | 2 / 8 | 2 / 8 | 4 / 8 | 7 / 9 | 4 / 9 |
| Accruals ratio | 26.5% | −2.4% | −7.2% | −2.7% | −5.6% | −11.5% | −9.5% | −15.9% |
| Altman Z'' | −8.01 | 7.12 | 24.00 | 11.93 | 10.19 | 7.63 | 9.07 | 6.15 |
8 years of figures
US$ millions unless stated. Hover a ratio's name for its definition.
| Fiscal year | FY18 | FY19 | FY20 | FY21 | FY22 | FY23 | FY24 | FY25 |
|---|---|---|---|---|---|---|---|---|
| Income statement | ||||||||
| Revenue | $22.8M | $51.9M | $62.6M | $94.1M | $137M | $220M | $332M | $344M |
| Gross profit | $17.5M | $44.6M | $53.0M | $78.3M | $105M | $175M | $272M | $273M |
| Research and development | $4.9M | $7.4M | $13.3M | $29.6M | $44.9M | $53.6M | $52.0M | $51.9M |
| Operating income | −$3.8M | $7.3M | −$6.5M | −$40.1M | −$72.9M | −$68.0M | $8.7M | −$42.8M |
| Interest expense | $2.3M | $4.6M | $2.6M | $0.0M | $0.0M | $0.0M | $0.6M | $0.1M |
| Income tax | $0.0M | $0.1M | $0.1M | −$8.7M | −$1.8M | $0.1M | $3.3M | −$5.4M |
| Net income | −$6.4M | $5.3M | −$10.3M | −$31.3M | −$67.1M | −$57.5M | $18.2M | −$24.2M |
| Net income to common | −$10.2M | $3.0M | −$10.3M | — | — | — | — | — |
| Diluted EPS | −$5.33 | −$0.21 | −$0.54 | −$1.24 | −$2.58 | −$2.14 | $0.62 | −$0.83 |
| Diluted shares | 0.00B | 0.01B | 0.02B | 0.03B | 0.03B | 0.03B | 0.03B | 0.03B |
| Cash flow | ||||||||
| Cash from operations | −$12.3M | $7.0M | $9.9M | −$19.0M | −$41.7M | −$5.6M | $64.9M | $64.3M |
| Capital expenditure | $0.3M | $0.9M | $4.8M | $3.5M | $5.6M | $13.6M | $28.3M | $36.0M |
| Free cash flow | −$12.6M | $6.1M | $5.1M | −$22.5M | −$47.3M | −$19.2M | $36.5M | $28.3M |
| Depreciation and amortization | $0.3M | $0.4M | $0.5M | $3.4M | $10.5M | $12.3M | $16.0M | $40.8M |
| Stock-based compensation | $0.3M | $1.2M | $8.3M | $21.7M | $36.3M | $51.2M | $50.3M | $45.9M |
| Acquisitions | — | — | — | $0.0M | $27.0M | $0.0M | $0.0M | — |
| Balance sheet | ||||||||
| Cash and short-term investments | $4.5M | $98.8M | $410M | $330M | $259M | $243M | $293M | $300M |
| Total debt | $24.5M | $26.7M | $0.0M | — | — | $0.0M | $10.0M | $10.1M |
| Finance lease liabilities | — | — | — | $0.2M | $0.2M | $0.1M | $0.4M | $0.4M |
| Current assets | $18.1M | $117M | $430M | $354M | $292M | $296M | $360M | $361M |
| Current liabilities | $6.7M | $15.3M | $20.9M | $24.9M | $36.1M | $47.7M | $49.4M | $68.7M |
| Inventory | $0.9M | $1.2M | $2.2M | $2.0M | $4.0M | $7.9M | $8.1M | $10.3M |
| Property and equipment, net | $1.5M | $2.1M | $7.1M | $9.5M | $14.3M | — | — | — |
| Goodwill | — | — | — | $0.0M | $10.7M | $10.7M | $10.7M | $10.7M |
| Intangible assets | $0.0M | $0.0M | $0.0M | $88.9M | $116M | $107M | $95.5M | $88.9M |
| Total assets | $22.4M | $120M | $439M | $463M | $447M | $453M | $531M | $579M |
| Total liabilities | $32.5M | $34.6M | $23.6M | $50.8M | $48.2M | $62.1M | $75.4M | $108M |
| Shareholders' equity | −$56.6M | $85.1M | $416M | $412M | $399M | $391M | $456M | $471M |
| Margins | ||||||||
| Gross margin | 76.8% | 85.9% | 84.5% | 83.2% | 76.6% | 79.5% | 81.9% | 79.4% |
| Operating margin | −16.8% | 14.1% | −10.4% | −42.6% | −53.2% | −30.9% | 2.6% | −12.4% |
| EBITDA margin | −15.6% | 14.8% | −9.7% | −39.0% | −45.5% | −25.3% | 7.4% | −0.6% |
| Net margin | −27.9% | 10.2% | −16.4% | −33.3% | −49.0% | −26.1% | 5.5% | −7.0% |
| FCF margin | −55.2% | 11.7% | 8.2% | −23.9% | −34.5% | −8.8% | 11.0% | 8.2% |
| Returns | ||||||||
| Return on capital | — | 44.7% | −88.5% | — | — | −36.2% | 4.0% | −18.6% |
| Return on capital employed | −24.5% | 7.0% | −1.6% | −9.2% | −17.7% | −16.8% | 1.8% | −8.4% |
| Return on equity | — | 37.0% | −4.1% | −7.6% | −16.6% | −14.5% | 4.3% | −5.2% |
| Return on assets | −28.4% | 7.4% | −3.7% | −6.9% | −14.8% | −12.8% | 3.7% | −4.4% |
| Return on tangible equity | — | 3.5% | −2.5% | −9.7% | −24.6% | −21.0% | 5.2% | −6.5% |
| Growth | ||||||||
| Revenue growth | — | 127.6% | 20.8% | 50.2% | 45.7% | 60.4% | 51.1% | 3.7% |
| Net income growth | — | — | −294.9% | — | — | — | — | −232.4% |
| EPS growth | — | — | — | — | — | — | — | −233.9% |
| FCF growth | — | — | −15.9% | −539.3% | — | — | — | −22.5% |
| Share count change | — | 354.2% | 118.6% | 32.8% | 3.6% | 2.9% | 9.2% | −0.9% |
| Financial health | ||||||||
| Net debt / EBITDA | — | −9.4x | — | — | — | — | −11.5x | — |
| Debt / equity | — | 0.3x | 0.0x | — | — | 0.0x | 0.0x | 0.0x |
| Interest coverage | −1.7x | 1.6x | −2.5x | −40,079.0x | −4,285.6x | −6,179.7x | 15.0x | −497.8x |
| Current ratio | 2.7x | 7.6x | 20.6x | 14.2x | 8.1x | 6.2x | 7.3x | 5.3x |
| Quick ratio | 2.6x | 7.6x | 20.5x | 14.1x | 8.0x | 6.0x | 7.1x | 5.1x |
| Capital allocation | ||||||||
| Capex / revenue | 1.2% | 1.8% | 7.6% | 3.7% | 4.1% | 6.2% | 8.5% | 10.5% |
| Stock comp / revenue | 1.3% | 2.4% | 13.3% | 23.1% | 26.5% | 23.3% | 15.2% | 13.3% |
| Quality scores | ||||||||
| Piotroski F-score | — | 7.0 | 4.0 | 2.0 | 2.0 | 4.0 | 7.0 | 4.0 |
| Altman Z'' | −8.0 | 7.1 | 24.0 | 11.9 | 10.2 | 7.6 | 9.1 | 6.1 |
| Accruals ratio | 26.5% | −2.4% | −7.2% | −2.7% | −5.6% | −11.5% | −9.5% | −15.9% |
Source: SEC EDGAR XBRL filings (CIK 0001447362). Data updated October 24, 2026. Quarterly fourth quarters are the full year minus the first nine months. For information only — not investment advice. Check the original filings before relying on any figure.