Castle Biosciences
CSTLNASDAQUSD
- Source valuation snapshot. Not a live recalculation.
- Latest filed annual earnings; price snapshot date unavailable. Not forward P/E.
- Diluted earnings per share from the latest filed annual.
- $34.42 Prior regular-session close from the quote source.
- $33.84–$36.00 Regular-session low and high so far today.
- 335.3K Regular-session shares traded · Nov 11, 4:00 PM ET.
- Not yet confirmed The company has not confirmed its next report date. Reported quarters are available in the chart’s Earnings view.
- $17.72–$44.28 52-week trading low and high returned by the quote source.
Understand the Business
Why the Stock Moved
Period-matched expectations history is not yet available. Current metrics are not a substitute for a historical explanation.
The core investment thesis
Own CSTL if physicians keep using its molecular diagnostics to make higher-confidence care decisions and payers keep reimbursing those tests at attractive economics.
CSTL price history
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Investment thesis
What must happen next
Clinicians will keep ordering Castle’s specialty molecular tests only if the results change treatment or surveillance decisions enough to overcome standard pathology and clinicopathologic risk models.HoldingMateriality: High
GAAP annual revenue increased from $94.1 million in FY2021 to $344.2 million in FY2025, evidence that the testing portfolio gained adoption over several years. If clinical utility remains persuasive, revenue can compound from physician adoption; if it weakens, Castle becomes a niche lab with limited pricing power.
Watch: Dermatology, oncology or gastroenterology guidelines emphasize conventional pathology and clinicopathologic risk models rather than molecular testing for Castle’s indications.
Supporting sources
Source notes are factual paraphrases; read the original disclosures below.
GAAP annual revenue increased from $94.1 million in FY2021 to $344.2 million in FY2025, evidence that the testing portfolio gained.
Open source ↗Coverage and collections from Medicare and commercial payers remain the economic moat: if payers continue accepting Castle’s clinical-utility case, high-value test orders can translate into cash even while GAAP investment continues.StrengtheningMateriality: High
GAAP annual operating cash flow improved from negative $41.7 million in FY2022 and negative $5.6 million in FY2023 to positive $64.9 million in FY2024. The owner is paid only if clinical adoption becomes collectible revenue, not merely test volume.
Watch: MolDX, CMS or a major commercial payer narrows coverage, lowers allowed reimbursement, increases prior authorization or demands additional prospective evidence for core tests.
Supporting sources
Source notes are factual paraphrases; read the original disclosures below.
GAAP annual operating cash flow improved from negative $41.7 million in FY2022 and negative $5.6 million in FY2023 to positive.
Open source ↗The centralized lab and specialist-commercial model should create operating leverage only if additional indications use existing infrastructure rather than requiring another step-up in sales, evidence-generation and billing expense.HoldingMateriality: Medium
GAAP annual operating income improved from negative $72.9 million in FY2022 and negative $68.0 million in FY2023 to positive $8.7 million in FY2024, showing the model can approach profitability at scale. If scale emerges, Castle can turn revenue into earnings; if each growth layer requires a new cost layer, revenue growth will not create much per-share value.
Watch: Expansion in Barrett’s esophagus, atopic dermatitis or uveal melanoma requires separate sales calls, specialty education, clinical studies and payer work rather than leveraging the dermatology-led infrastructure.
Supporting sources
Source notes are factual paraphrases; read the original disclosures below.
GAAP annual operating income improved from negative $72.9 million in FY2022 and negative $68.0 million in FY2023 to positive $8.7.
Open source ↗Castle can keep funding evidence generation, launches and reimbursement defense internally if positive cash generation and its cash reserve persist, limiting forced dilution or debt during payer and product cycles.StrengtheningMateriality: Medium
Cash and equivalents were $116.7 million at FY2025 year-end, roughly stable versus $119.7 million at FY2024 year-end. A strong balance sheet lets management play the long clinical-evidence game; a cash drain would shift value from owners to financiers.
Watch: Large prospective clinical-utility studies or reimbursement disputes require spending materially above internally generated cash.
Supporting sources
Source notes are factual paraphrases; read the original disclosures below.
Cash and equivalents were $116.7 million at FY2025 year-end, roughly stable versus $119.7 million at FY2024 year-end.
Open source ↗
Full investment case & evidence
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Original research
Clinicians will keep ordering Castle’s specialty molecular tests only if the results change treatment or surveillance decisions enough to overcome standard pathology and clinicopathologic risk models. If clinical utility remains persuasive, revenue can compound from physician adoption; if it weakens, Castle becomes a niche lab with limited pricing power.
Coverage and collections from Medicare and commercial payers remain the economic moat: if payers continue accepting Castle’s clinical-utility case, high-value test orders can translate into cash even while GAAP investment continues. The owner is paid only if clinical adoption becomes collectible revenue, not merely test volume.
The centralized lab and specialist-commercial model should create operating leverage only if additional indications use existing infrastructure rather than requiring another step-up in sales, evidence-generation and billing expense. If scale emerges, Castle can turn revenue into earnings; if each growth layer requires a new cost layer, revenue growth will not create much per-share value.
Castle can keep funding evidence generation, launches and reimbursement defense internally if positive cash generation and its cash reserve persist, limiting forced dilution or debt during payer and product cycles. A strong balance sheet lets management play the long clinical-evidence game; a cash drain would shift value from owners to financiers.
All standing thesis claims
Original report summary
physicians keep using its molecular diagnostics to make higher-confidence care decisions and payers keep reimbursing those tests at attractive economics.
Bull case and bear case
Bull case and bear case for Castle Biosciences
Where the evidence on Castle Biosciences stands: Holding on the latest evidence (Nov 7, 2026). Of its 4 thesis points, 2 strengthening and 2 holding.
Bull case: what the evidence supports
Clinicians will keep ordering Castle’s specialty molecular tests only if the results change treatment or surveillance decisions enough to overcome standard pathology and clinicopathologic risk models.
Coverage and collections from Medicare and commercial payers remain the economic moat: if payers continue accepting Castle’s clinical-utility case, high-value test orders can translate into cash even while GAAP investment continues.
The centralized lab and specialist-commercial model should create operating leverage only if additional indications use existing infrastructure rather than requiring another step-up in sales, evidence-generation and billing expense.
Castle can keep funding evidence generation, launches and reimbursement defense internally if positive cash generation and its cash reserve persist, limiting forced dilution or debt during payer and product cycles.
Bear case: what would count against it
Dermatology, oncology or gastroenterology guidelines emphasize conventional pathology and clinicopathologic risk models rather than molecular testing for Castle’s indications.
MolDX, CMS or a major commercial payer narrows coverage, lowers allowed reimbursement, increases prior authorization or demands additional prospective evidence for core tests.
Expansion in Barrett’s esophagus, atopic dermatitis or uveal melanoma requires separate sales calls, specialty education, clinical studies and payer work rather than leveraging the dermatology-led infrastructure.
Thesis-Break Engine
Thesis-break watch · Castle Biosciences
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MARKET + FINANCIAL SNAPSHOT
The numbers behind the thesis
What Changed
- MixedReported results of operations (earnings release).
Castle Biosciences filed an SEC 8-K on 2026-11-05: Reported results of operations (earnings release). It is a dated development that tests the current thesis.
- MixedReported results of operations (earnings release).
Castle Biosciences filed an SEC 8-K on 2026-07-30: Reported results of operations (earnings release). It is a dated development that tests the current thesis.
- MixedReported results of operations (earnings release).
Castle Biosciences filed an SEC 8-K on 2026-05-06: Reported results of operations (earnings release). It is a dated development that tests the current thesis.
Risks / falsifiers
What could break the thesis
- Dermatology, oncology or gastroenterology guidelines emphasize conventional pathology and clinicopathologic risk models rather than molecular testing for Castle’s indications.
- MolDX, CMS or a major commercial payer narrows coverage, lowers allowed reimbursement, increases prior authorization or demands additional prospective evidence for core tests.
- Expansion in Barrett’s esophagus, atopic dermatitis or uveal melanoma requires separate sales calls, specialty education, clinical studies and payer work rather than leveraging the dermatology-led infrastructure.
- Large prospective clinical-utility studies or reimbursement disputes require spending materially above internally generated cash.
CSTL news
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Financial statements
CSTL income statement
Annual filed results · USD · Oldest to newest. Margins are calculated from the reported figures.