Forensic Analysis · Healthcare / Pharmaceuticals / Biotech · as of Jun 27, 2026
CASTLE BIOSCIENCES INC (CSTL)
A forensic read on CASTLE BIOSCIENCES INC built from its complete SEC filings — financial-health screens, earnings quality, red flags and a price-aware rating. Reproducible math, not opinion.
C · Mixed — selective
Forensic grade
Safe
Financial health
6.2
Altman Z-score
Clean
Earnings quality
3
Forensic signals
-2.8%
ROE
$737M
Market cap
CASTLE BIOSCIENCES INC earns a C (Mixed — selective) forensic quality grade, and its Altman Z-score is 6.2, placing it in the Safe zone. 3 forensic signals were flagged in its latest SEC filings, led by return on invested capital.
What the filings flag
-9%Return on invested capital.Return on invested capital is -9% and rising from -20% — well below its ~10% cost of capital, so reinvested dollars may be destroying value, not building it.
+3.8%/yrShare-count dilution.Diluted share count changed +11% over the last 3 years to FY2025 (+3.8%/yr). The count is GROWING — existing holders are being diluted. That's ~3.8% shaved off per-share growth every year — total profit has to grow that much just to keep earnings-per-share flat, and a stake held since FY2022 has been diluted ~11%.
13% of revStock-based comp load.Stock-based compensation ran 13% of revenue and 162% of free cash flow in FY2025 — about $1.58 per diluted share. Heavy — a large slice of 'free cash flow' is really being paid out in stock, so the true owner cash per share is well below the headline.
Key fundamentals
Net Margin-7.0%
Debt / Equity0.02x
Free Cash Flow$28.3M
Latest Revenue$344.2M
Return on Equity-5.1%
Revenue Growth YoY+3.7%
Go deeper — free with an account
The forensic grade and screens above are free — no account needed. An account adds the full interactive deep-dive on CASTLE BIOSCIENCES INC:
🔒The written investment read — what the numbers mean, in plain English
🔒Ask anything about CSTL's filings — AI Q&A across the 10-K, 10-Qs & 8-Ks
🔒Interactive valuation — reverse-DCF sliders, Monte Carlo & scenario stress
🔒Calibrated 12-month price forecast, with the math shown