Castle Biosciences Inc.
Castle Biosciences (Nasdaq: CSTL) is a molecular diagnostics company that develops and provides tests to help clinicians diagnose and manage dermatologic cancers, Barrett’s esophagus, atopic dermatitis and uveal melanoma. Its tissue-based tests use molecular analysis and algorithms to provide patient-specific… From the company’s description.
Over the twelve months to Sep 30, 2026, Castle Biosciences Inc. reported revenue of $377.13M, up 9.8% from a year earlier, and a net loss of $23.01M. Its operating margin was −7.4%, and operations generated $39.74M in cash. In fiscal 2025, it reported revenue of $344.23M, up 3.7% from fiscal 2024, and a net loss of $24.16M.
Margins and return on equity change in ; everything else in percent. Fewer shares and less debt are shown plainly, not as bad news — it depends what you make of buybacks. Dotted labels explain each measure. is shown separately from the annual figures.
What Castle Biosciences Inc. does
In the company’s own words
Castle Biosciences (Nasdaq: CSTL) is a molecular diagnostics company that develops and provides tests to help clinicians diagnose and manage dermatologic cancers, Barrett’s esophagus, atopic dermatitis and uveal melanoma. Its tissue-based tests use molecular analysis and algorithms to provide patient-specific information for clinical care decisions, including risk stratification and potential response to treatment. Products include DecisionDx-Melanoma, DecisionDx-SCC, MyPath Melanoma, TissueCypher, DecisionDx-UM and the recently launched AdvanceAD-Tx, which is designed to guide systemic treatment selection for patients with moderate-to-severe atopic dermatitis. The company primarily serves clinicians, with sales and marketing focused on U.S. dermatology and gastroenterology markets; revenue is primarily generated through reimbursement from government and commercial payors. Castle operates clinical laboratories in Arizona and Pennsylvania and reports its business as a single company rather than describing reportable operating segments. In 2025, it delivered 105,053 test reports and generated $344.2 million in net revenue. Its acquisitions have expanded its portfolio, including the 2025 acquisition of Previse, which added Barrett’s esophagus-related intellectual property and cell-collection technology. Its website is www.castlebiosciences.com.
Company details
- Sector
- Health Care
- Industry (SIC)
- Health Services
- Headquarters
- FRIENDSWOOD, TX
- Fiscal year end
- December
- CIK
- 1447362
- SIC
- 8071
Financial performance, year by year
Fiscal 2019–2025 · USDThe full income statement, balance sheet and cash flow for each of these years — every figure traceable to its filing — is on the Financials tab with a free account.
Who owns Castle Biosciences Inc. — and what changed
Funds as of 2026Q2 · superinvestors as of 2026-06-30
Largest fund holders · Castle Biosciences Inc.’s weight in each
Fund ownership is a floor, not a census — pensions, insurers and people holding shares directly are not visible here.
Fund ownership counts N-PORT filers only, so it is a floor rather than a census — pensions, insurers and direct holders are not visible here, and the remainder is not “held by individuals”.
Every fund and institutional holder, quarter by quarter, is on the Ownership tab with a free account.
Recent filings
All filings →Each filing opens into its own statements and disclosures here.
Put this business in context.
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