Castle Biosciences, Inc. (CSTL) Cash Flow Statement
Where CSTL’s cash came from and went, 2025
December 31, 2025 · U.S. dollars- Cash from operations
- $64.3M −0.8% vs 2024
- Capital expenditures
- $36.0M 10.5% of revenue
- Free cash flow
- $28.3M 8.2% margin
- Returned to shareholders
- —
- Change in cash
- −$3.0M cash at year-end $116.7M
Cash from operations
$64.3M
Capital expenditures
−$36.0M
Investments (net)
+$2.0M
Acquisitions & other
−$26.4M
Other financing
−$7.0M
Change in cash
−$3.0M
Drawn to scale: where the cash came from and how it was used. Hover for values.
CSTL operating cash flow, capex and free cash flow
Operating cash flowCapital expendituresFree cash flowFCF margin (right axis)
CSTL cash flow trends, 2017–2025
| Metric | Trend | Then | Latest | Change |
|---|---|---|---|---|
| Operating cash flow | −$12.2M2017 | $64.3M2025 | — | |
| Capital expenditures | $494,8542017 | $36.0M2025 | +70.9%/yr | |
| Free cash flow | −$12.7M2017 | $28.3M2025 | — | |
| Free cash flow margin | −92.5%2017 | 8.2%2025 | +100.8 pts | |
| Operating cash flow / net income | 1.332019 | 3.562024 | +2.23 | |
| Stock-based compensation | $108,6962017 | $45.9M2025 | +112.9%/yr | |
| Dividends paid | $02017 | $1.7M2022 | — | |
| Share buybacks (net) | $02017 | $5.1M2023 | — | |
| Capex / revenue | 3.6%2017 | 10.5%2025 | +6.9 pts |
Change is the average annual growth (CAGR) or the difference between the first and latest year.
CSTL cash flow by activity
OperatingInvestingFinancingChange in cash
CSTL net income vs operating cash flow
Net incomeOperating cash flow
Operating cash flow above net income usually means earnings are backed by cash (depreciation and stock-based pay are non-cash expenses).
CSTL cash flow statement
| 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|
| Operating activities | |||||||||
| Net income | −$24.2M | $18.2M | −$57.5M | −$67.1M | −$31.3M | −$10.3M | $5.3M | −$6.4M | −$12.4M |
| Depreciation & amortization | $40.8M | $16.0M | $12.3M | $10.5M | $3.4M | $472,000 | $358,000 | $323,016 | $310,820 |
| Stock-based compensation | $45.9M | $50.3M | $51.2M | $36.3M | $21.7M | $8.3M | $1.2M | $293,639 | $108,696 |
| Change in working capital | $13.6M | −$14.1M | −$6.6M | −$7,000 | −$4.1M | $9.1M | $44,000 | −$7.4M | −$640,514 |
| Other non-cash items | −$11.8M | −$5.6M | −$5.1M | −$21.4M | −$8.7M | $2.2M | $87,000 | $814,790 | $356,940 |
| Cash from operating activities | $64.3M | $64.9M | −$5.6M | −$41.7M | −$19.0M | $9.9M | $7.0M | −$12.3M | −$12.2M |
| Investing activities | |||||||||
| Capital expenditures | −$36.0M | −$28.3M | −$13.6M | −$5.6M | −$3.5M | −$4.8M | −$937,000 | −$277,036 | −$494,854 |
| Investments (net) | $2.0M | −$50.1M | −$13.0M | −$166.5M | −$66.7M | −$4.7M | −$937,000 | −$277,036 | −$494,854 |
| Acquisitions & other investing | −$26.4M | $28.3M | $10.4M | $5.6M | $3.5M | $4.8M | $937,000 | $277,036 | $494,854 |
| Cash from investing activities | −$60.4M | −$50.1M | −$16.2M | −$166.5M | −$66.7M | −$4.7M | −$937,000 | −$277,036 | −$494,854 |
| Financing activities | |||||||||
| Dividends paid | — | — | — | −$1.7M | −$3.1M | — | — | $0 | $0 |
| Share repurchases & issuance (net) | — | — | −$5.1M | −$1.7M | −$781,000 | — | $67.2M | $10.4M | $292,710 |
| Net borrowing (repayment) | $75,000 | $9.9M | −$142,000 | −$122,000 | −$8,000 | −$27.4M | $20.9M | $5.4M | $25.7M |
| Shares issued | $0 | $0 | $0 | $0 | $250.5M | $330.0M | $66.0M | $10.4M | $0 |
| Other financing | −$7.0M | −$3.8M | $3.0M | $5.0M | −$241.2M | $3.2M | −$65.8M | −$10.4M | −$17.1M |
| Cash from financing activities | −$7.0M | $6.1M | −$2.3M | $1.5M | $5.4M | $305.9M | $88.3M | $15.8M | $8.9M |
| Summary | |||||||||
| Net change in cash | −$3.0M | $20.9M | −$24.1M | −$206.7M | −$80.2M | $311.0M | $94.4M | $3.3M | −$3.9M |
| Cash at end of period | $116.7M | $119.7M | $98.8M | $122.9M | $329.6M | $409.9M | $98.8M | $4.5M | $1.2M |
| Free cash flow | $28.3M | $36.5M | −$19.2M | −$47.3M | −$22.5M | $5.1M | $6.1M | −$12.6M | −$12.7M |
| Free cash flow margin | 8.2% | 11.0% | −8.8% | −34.5% | −23.9% | 8.2% | 11.7% | −55.2% | −92.5% |
| Capex / revenue | 10.5% | 8.5% | 6.2% | 4.1% | 3.7% | 7.6% | 1.8% | 1.2% | 3.6% |
| Operating cash flow / net income | — | 3.56 | — | — | — | — | 1.33 | — | — |
| Jun '26 | Mar '26 | Dec '25 | Sep '25 | Jun '25 | Mar '25 | Dec '24 | Sep '24 | Jun '24 | Mar '24 | Dec '23 | Sep '23 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Operating activities | ||||||||||||
| Net income | −$2.1M | −$14.5M | −$2.3M | −$501,000 | $4.5M | −$25.8M | $9.6M | $2.3M | $8.9M | −$2.5M | −$2.6M | −$6.9M |
| Depreciation & amortization | $4.1M | $3.9M | $3.8M | $3.8M | $3.4M | $29.8M | $5.8M | $3.5M | $3.3M | $3.3M | $3.2M | $3.2M |
| Stock-based compensation | $11.6M | $9.8M | $11.4M | $12.1M | $11.2M | $11.2M | $11.4M | $13.0M | $13.2M | $12.7M | $11.8M | $13.0M |
| Change in working capital | $1.1M | −$19.4M | $14.0M | $11.5M | $8.5M | −$20.4M | $2.0M | $776,000 | $1.9M | −$18.8M | $7.7M | −$2.8M |
| Other non-cash items | $470,000 | −$2.0M | $111,000 | −$4.3M | −$6.8M | −$750,000 | −$4.4M | $3.7M | −$3.4M | −$1.5M | −$1.5M | −$1.5M |
| Cash from operating activities | $15.2M | −$22.1M | $26.9M | $22.6M | $20.8M | −$6.0M | $24.4M | $23.3M | $24.0M | −$6.8M | $18.6M | $5.0M |
| Investing activities | ||||||||||||
| Capital expenditures | −$8.7M | −$12.5M | −$7.2M | −$14.8M | −$9.3M | −$4.7M | −$7.6M | −$6.4M | −$5.2M | −$9.2M | −$3.8M | −$2.5M |
| Investments (net) | −$7.3M | −$13.4M | $23.7M | −$18.4M | −$28.4M | −$22.4M | $5.8M | −$14.8M | −$21.4M | −$19.7M | −$7.7M | −$9.7M |
| Acquisitions & other investing | $6,000 | $7,000 | −$7.7M | $14.8M | $9.3M | $4.7M | $7.6M | $6.4M | $5.2M | $9.2M | $3.8M | $2.5M |
| Cash from investing activities | −$16.0M | −$25.8M | $8.8M | −$18.4M | −$28.4M | −$22.4M | $5.8M | −$14.8M | −$21.4M | −$19.7M | −$7.7M | −$9.7M |
| Financing activities | ||||||||||||
| Dividends paid | — | — | — | — | — | — | — | — | — | — | — | −$258,000 |
| Share repurchases & issuance (net) | — | — | — | — | — | — | — | $1.1M | −$615,000 | −$474,000 | −$4.0M | −$271,000 |
| Net borrowing (repayment) | −$24,000 | −$24,000 | −$27,000 | −$31,000 | $159,000 | −$26,000 | −$26,000 | −$24,000 | — | — | — | — |
| Shares issued | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Other financing | −$862,000 | −$5.0M | −$4.6M | −$888,000 | −$58,000 | −$1.5M | −$5.4M | −$227,000 | $657,000 | $11.1M | $718,000 | $574,000 |
| Cash from financing activities | −$886,000 | −$5.0M | −$4.6M | −$919,000 | $101,000 | −$1.6M | −$5.4M | $838,000 | $42,000 | $10.6M | −$3.3M | $45,000 |
| Summary | ||||||||||||
| Net change in cash | −$1.6M | −$53.0M | $31.2M | $3.3M | −$7.5M | −$30.0M | $24.8M | $9.4M | $2.6M | −$15.9M | $7.6M | −$4.7M |
| Cash at end of period | $62.1M | $63.8M | $116.7M | $85.6M | $82.2M | $89.7M | $119.7M | $95.0M | $85.6M | $82.9M | $98.8M | $91.2M |
| Free cash flow | $6.6M | −$34.6M | $19.7M | $7.8M | $11.6M | −$10.8M | $16.8M | $17.0M | $18.8M | −$16.0M | $14.8M | $2.6M |
| Free cash flow margin | 6.3% | −41.3% | 22.7% | 9.4% | 13.4% | −12.2% | 19.5% | 19.8% | 21.6% | −21.9% | 22.4% | 4.2% |
| Capex / revenue | 8.4% | 14.9% | 8.3% | 17.9% | 10.7% | 5.4% | 8.8% | 7.4% | 6.0% | 12.5% | 5.7% | 4.0% |
| Operating cash flow / net income | — | — | — | — | 4.60 | — | 2.54 | 10.29 | 2.69 | — | — | — |
Negative numbers are cash paid out. Quarterly columns are labeled by the month the quarter ended. Figures in U.S. dollars as reported; data from EODHD.
CSTL cash generation
In fiscal 2025 (ended December 31, 2025), Castle Biosciences generated $64.3 million of cash from operations (down 0.8%) and spent $36.0 million on capital expenditures, leaving free cash flow of $28.3 million, 8.2% of revenue. Cash and equivalents fell by $3.0 million over the year.
Related: CSTL income statement, CSTL balance sheet. See the CSTL stock overview for the latest quote and news.
CSTL cash flow FAQ
What is Castle Biosciences's free cash flow?
Castle Biosciences's free cash flow was $28.3 million in fiscal 2025: $64.3 million of operating cash flow minus $36.0 million of capital expenditures It was $36.5 million a year earlier..
How much cash does Castle Biosciences generate from operations?
Castle Biosciences generated $64.3 million of cash from operating activities in fiscal 2025.
How much does Castle Biosciences spend on capital expenditures?
Castle Biosciences spent $36.0 million on capital expenditures in fiscal 2025, 10.5% of revenue, compared with $28.3 million the year before.