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Castle Biosciences, Inc. (CSTL)

Castle Biosciences, Inc. at a glance — key fundamentals, SEC filings, insider buying and selling, and earnings dates.

Castle Biosciences, Inc. (CSTL) is a Medical - Diagnostics & Research company based in US with a market capitalization of $640.9M. Revenue grew 3.7% year-over-year and the company generated $28.3M in free cash flow. This page tracks CSTL's SEC filings, insider buying and selling, earnings dates, and key fundamentals in one place.

US · 784 employees · IPO Jul 25, 2019

Valuation

Valuation & price

$19.13 · as of May 17, 2026 · -55.6% vs 52w high

—

P/E ratio

Latest-FY diluted EPS

1.36

P/B ratio

Market cap ÷ book equity

—

Dividend yield

Price — last 12 months

$42.84$29.00$15.15Jul 25Dec 25Jul 26Jul 7, 25$19.46Jul 9, 25$20.12Jul 11, 25$19.66Jul 15, 25$18.87Jul 17, 25$17.39Jul 21, 25$16.72Jul 23, 25$16.80Jul 25, 25$16.07Jul 29, 25$16.23Jul 31, 25$15.15Aug 4, 25$15.32Aug 6, 25$19.76Aug 11, 25$19.16Aug 13, 25$19.41Aug 15, 25$20.09Aug 19, 25$19.90Aug 21, 25$19.97Aug 25, 25$20.57Aug 27, 25$22.28Aug 29, 25$24.01Sep 3, 25$23.20Sep 5, 25$23.56Sep 9, 25$24.65Sep 11, 25$22.75Sep 16, 25$21.75Sep 18, 25$23.46Sep 22, 25$24.08Sep 24, 25$22.67Sep 26, 25$22.71Sep 30, 25$22.77Oct 2, 25$22.23Oct 6, 25$23.31Oct 8, 25$23.59Oct 10, 25$23.08Oct 14, 25$22.36Oct 16, 25$22.53Oct 21, 25$23.40Oct 23, 25$24.18Oct 27, 25$23.96Oct 29, 25$23.74Oct 31, 25$25.50Nov 4, 25$31.63Nov 6, 25$33.55Nov 10, 25$34.74Nov 12, 25$34.82Nov 14, 25$33.45Nov 18, 25$33.55Nov 20, 25$35.72Nov 25, 25$39.93Nov 28, 25$39.95Dec 2, 25$39.10Dec 4, 25$39.62Dec 8, 25$38.10Dec 10, 25$38.02Dec 12, 25$38.63Dec 16, 25$39.05Dec 18, 25$39.60Dec 22, 25$41.39Dec 24, 25$40.09Dec 29, 25$39.27Jan 2, 26$38.54Jan 6, 26$40.07Jan 8, 26$39.89Jan 12, 26$39.66Jan 14, 26$40.77Jan 16, 26$40.01Jan 21, 26$40.98Jan 23, 26$42.24Jan 27, 26$42.84Jan 29, 26$39.16Feb 2, 26$39.47Feb 4, 26$34.96Feb 9, 26$32.23Feb 11, 26$32.34Feb 13, 26$33.15Feb 18, 26$33.67Feb 20, 26$29.21Feb 24, 26$29.94Feb 26, 26$31.88Mar 2, 26$27.99Mar 4, 26$28.17Mar 6, 26$27.12Mar 10, 26$26.60Mar 12, 26$25.32Mar 17, 26$25.90Mar 19, 26$25.70Mar 23, 26$25.75Mar 25, 26$25.27Mar 27, 26$23.53Mar 31, 26$24.55Apr 2, 26$24.84Apr 7, 26$24.83Apr 9, 26$23.43Apr 13, 26$23.53Apr 15, 26$24.62Apr 17, 26$25.05Apr 22, 26$25.10Apr 24, 26$24.46Apr 28, 26$24.69Apr 30, 26$24.49May 4, 26$25.52May 6, 26$24.75May 8, 26$19.83May 12, 26$18.63May 14, 26$18.88May 18, 26$19.32May 20, 26$20.03May 22, 26$20.15May 28, 26$22.11Jun 1, 26$20.97Jun 3, 26$20.39Jun 5, 26$21.01Jun 9, 26$21.08Jun 11, 26$21.01Jun 15, 26$20.66Jun 17, 26$20.25Jun 22, 26$21.20Jun 24, 26$22.12Jun 26, 26$24.30Jul 2, 26$24.11
$14.6552-week range$43.04
Loading valuation history…

Fundamentals

Key fundamentals

$640.9M

Market cap

3.7%

Revenue growth (YoY)

79.4%

Gross margin

$28.3M

Free cash flow (USD)

-$262.6M

Net debt

Net cash position

4.4%

Share dilution

2/5

Graham criteria passed

Defensive-investor screen

Healthcare

Sector

Trajectory

Long-term trends

Revenue by year

2017 → 2025

FY 2017$13.8MFY 2018$22.8MFY 2019$51.9MFY 2020$62.6MFY 2021$94.1MFY 2022$137.0MFY 2023$219.8MFY 2024$332.1MFY 2025$344.2M
$13.8M$344.2M

Free cash flow by year

2017 → 2025

FY 2017$-12.7MFY 2018$-12.6MFY 2019$6.1MFY 2020$5.1MFY 2021$-22.5MFY 2022$-47.3MFY 2023$-19.2MFY 2024$36.5MFY 2025$28.3M
-$12.7M$28.3M

Gross margin by year

2021 → 2025

FY 202183.2%FY 202276.6%FY 202379.5%FY 202481.9%FY 202579.4%
83.2%79.4%

Value screen

Graham defensive-investor tests

Computing the scorecard — refreshing any stale inputs…

0

Insider buys · 90 days

7

Insider sells · 90 days

Earnings

Last report: 10-Q filed May 6, 2026

Next expected: not yet scheduled

On the tape

Recent SEC & insider activity

  • Insider sellInsider Sell $178K · 10b5-1 PlanOelschlager Kristen M · Chief Operating Officer · $177.8KJun 18, 2026Filing
  • Insider sellInsider Sell $86K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $86.2KJun 17, 2026Filing
  • Insider sellInsider Sell $205K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $205.1KJun 3, 2026Filing
  • 8-K eventAnnual Meeting ResultsMay 29, 2026Filing
  • Insider sellInsider Sell $84K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $84.1KMay 22, 2026Filing
  • Insider sellInsider Sell $218K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $217.9KMay 11, 2026Filing
  • 8-K eventEarnings ReleaseMay 6, 2026Filing
  • Quarterly report10-Q FiledMay 6, 2026Filing
  • Insider sellInsider Sell $105K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $104.7KApr 23, 2026Filing
  • Insider sellInsider Sell $246K · 10b5-1 PlanMAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · $246.2KApr 8, 2026Filing

Questions

Frequently asked questions

What is Castle Biosciences, Inc.'s market cap?

Castle Biosciences, Inc. (CSTL) has a market capitalization of $640.9M.

What is CSTL's P/E ratio?

A meaningful P/E ratio is not available for CSTL — the company's latest fiscal-year earnings per share is zero, negative, or not yet cached.

What is CSTL's price-to-book (P/B) ratio?

CSTL trades at 1.36 times book value per share.

Are insiders buying CSTL stock?

SEC Form 4 filings show no open-market insider buys at Castle Biosciences, Inc. in the last 90 days (7 sells).

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Timeline

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News

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Data: SEC EDGAR filings and cached fundamental data; prices and ratios use the most recent cached quote and statements (may lag by up to a day). Educational and research purposes only. Not investment advice.