Castle Biosciences, Inc.

castlebiosciences.com

What Do They Do?

Sells diagnostic tests that help clinicians guide care for skin cancers, esophageal conditions and other diseases.

How Do They Make Money?

Clinicians order a test for a patient; Castle bills when it delivers the report. Medicare and commercial insurers provide most payments, and collection timing varies with coverage and payer practices.

revenue

Segment	Share	Revenue	How money arrives
Dermatologic Sold outright	63% FY2022: 91%		Sold outright
Non Dermatologic Sold outright	37% FY2022: 8.9%		Sold outright

Who Are Their Customers?

Clinicians order tests for patients, and Castle bills third-party payors and patients. Most payments come from Medicare and commercial insurers.

Customers above 10% of revenue, FY2025

of revenue from two customers (44%, 16%)

FY2024: 47% from one customer

Do Revenues Turn Into Profits?

Not on paper. It lost $24.2M in FY2025, but brought in more cash than it spent: $28.3M of free cash flow.

Operating income, FY2025

−12% of revenue

▼ Now a loss vs FY2024 ($8.7M, 3%)

Net income, FY2025

−7% of revenue

▼ Now a loss vs FY2024 ($18.2M, 5%)

Free cash flow, FY2025

8% of revenue

▼ −22% vs FY2024 ($36.5M, 11%)

How Are They Changing?

Since the FY2025 annual report

Latest quarter: Q2 FY2026, the three months to Jun 30, 2026

Revenue: ▲ +20%; vs $86.2M in Q2 FY2025
Net income: ▼ Now a loss; vs $4.5M in Q2 FY2025

Dermatologic share of revenue vs 65.3% in Q2 FY2025

Jul 30, 2026 Raised full-year revenue guidance Raised 2026 revenue guidance to $365-375 million from $345-355 million.
May 6, 2026 Raised full-year revenue guidance Raised 2026 revenue guidance to $345-355 million from $340-350 million.

Growing. Revenue grew 3.7x in 4 years, from $94.1M in FY2021 to $344.2M in FY2025, about 38% a year.

Broader gastrointestinal testing The older report described TissueCypher as the company's gastroenterology entry; the latest report adds Previse’s methylation-based intellectual property and a supplemental Esopredict test planned for inconclusive TissueCypher cases.

Atopic dermatitis test launched The older report described testing for systemic-treatment response in atopic dermatitis as a pipeline project; the latest report describes AdvanceAD-Tx as a launched test to guide treatment selection.

Mental health test discontinued The older report included IDgenetix in its commercial portfolio; the latest report says the test was discontinued.

Revenue over time

Dermatologic Non Dermatologic Other

$500M$250M$0

FY2021 FY2022 FY2023 FY2024 FY2025

Who Do They Compete With?

Competes with SkylineDx, Interpace Diagnostics, and Lucid Diagnostics

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