Castle Biosciences (CSTL) Stock Fundamentals, Analysis & Risk Signals

Health score, price, valuation, risk signals, and key metrics at a glance.

Castle Biosciences

NasdaqGM•Healthcare•Diagnostics & Research

$32.33+0.01(<0.01%)Market closed

Market Cap

$1.08B

P/S

3.0x

P/B

2.3x

Castle Biosciences, Inc., a molecular diagnostics company, provides test solutions for the diagnosis and treatment of dermatologic cancers, Barrett's esophagus (BE), atopic dermatitis (AD), and uveal melanoma. The company offers DecisionDx-Melanoma, a risk stratification gene expression profile (GEP) test that predicts the likelihood of a positive sentinel lymph node and the risk of metastasis for patients with invasive cutaneous melanoma; TissueCypher, a risk stratification spatialomics test to predict future development of high-grade dysplasia and/or esophageal cancer in patients with non-dysplastic, indefinite dysplasia, and low-grade dysplasia BE; AdvanceAD-Tx, a non-invasive GEP test which is designed to guide systemic treatment selection for patients aged 12 years and older with moderateto-severe AD; DecisionDx-SCC, a GEP test for cutaneous squamous cell carcinoma; and MyPath Melanoma, a diagnostic GEP test for use in patients with difficult-to-diagnose melanocytic lesions. It also provides DecisionDx-UM, a risk stratification GEP test that predicts the risk of metastasis for patients with uveal melanoma. The company offers its products to dermatology and gastroenterology markets. The company was incorporated in 2007 and is headquartered in Friendswood, Texas.

How this company scores

WeakMetricSide Score: 51/100

Grade capped at D — Interest coverage below 1× (-41.6x) — earnings cannot cover interest. Strongest: Balance Sheet & Red Flags (17/25); weakest: Growth (9/25).

Profitability11/25

Growth9/25

Balance Sheet & Red Flags17/25

Cash & Earnings Quality14/25

Strengths

Long cash runwayLow leverageCash-backed earningsImproving leverage

Grade capped at D

Interest coverage below 1× (-41.6x) — earnings cannot cover interest.

Valuation vs. 5-year range

Today's multiple positioned against its own trailing range — a visual premium/discount check.

P/E · 41.1x5y range 41.1x – 130.7x

P/S · 3.0x5y range 1.7x – 19.0x

Currently near its 20-quarter median.

P/B · 2.3x5y range 0.9x – 4.0x

Watch items

Data-driven signals worth keeping an eye on across the last 8 quarters

High Risk

Margin Pressure

Red Flag

The company posted negative operating margins in recent quarters — core operations are unprofitable.

Earnings Quality

Watch

FCF/Net Income has dropped below 0.7x in 4 quarters — monitor for earnings quality deterioration.

Price & Volume

Market Cap $1.08B

Metrics at a Glance

as of June 2026

Revenue & Profit

Revenue, EBITDA, operating income, net income, EPS, and shares

TTM Revenue: $357.28M
Q. Revenue: $103.55M
TTM EBITDA: $-16.52M
TTM Op. Income: $-32.11M
Q. Op. Income: $-3.07M
TTM Net Income: $-19.41M
Q. Net Income: $-2.06M
EPS: $-0.07
Shares Out.: $30.40M

$357.28M in TTM revenue grew 3.2% YoY, reaching $103.55M last quarter. TTM EBITDA of $-16.52M and TTM operating income of $-32.11M show growth is flowing through to the bottom line. However, net income is negative at $19.41M — growth is not yet reaching the bottom line. Over the past year, TTM revenue is up 3% — an improving trend.

Margins

Gross, EBITDA, operating, and net margin trends

Gross Margin: 77.1%
EBITDA Margin: 1.0%
Op. Margin: -3.0%
Net Margin: -2.0%

Op. margin of -3.0% is up 2.0% YoY — cost efficiency is improving. Net margin at -2.0% and gross margin of 77.1% show how much of each revenue dollar survives to profit. Over the past year, operating margin is up 40% — an improving trend.

Price Ratios

P/E, P/S, P/B, EV/EBITDA, FCF yield, and earnings yield

P/E Ratio: N/A
P/S Ratio: 3.0x
P/B Ratio: 2.3x

P/S of 3.0x and P/B of 2.3x. Over the past year, P/E is up 0% — an improving trend.

Assets & Liabilities

Total assets, cash, debt, book value, and leverage

Total Assets: $561.18M
Cash: $62.12M
Long-Term Debt: $7.16M
Book Value: $470.03M
D/E Ratio: 0.0
Debt/EBITDA: 7.2

With $561.18M in assets and $7.16M in long-term debt, D/E is 0.0and book value is $470.03M — a conservative capital structure with a cushion to weather downturns. Across the last 8 quarters, debt/equity has fallen for 3 consecutive quarters — an improving trend.

Cash Flow

Operating cash flow, free cash flow, FCF margin, and earnings quality

Op. Cash Flow: $15.20M
TTM Free Cash Flow: $-489,000
FCF Margin: -0.1%
FCF / Net Income: 0.0

TTM FCF of $-489,000 on $15.20M in operating cash flow. The FCF / Net Income ratio of 0.0x means cash covers only part of net income — earnings quality needs attention. Across the last 8 quarters, free cash flow has fallen for 2 consecutive quarters — a weakening trend.