Castle Biosciences (CSTL) Shares Outstanding (2018 - 2026)
Castle Biosciences (CSTL) posted Shares Outstanding of 30.4 million for Q2 2026, up 5.1% from 28.91 million a year earlier and up 1.7% from the prior quarter.
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Analysis
Castle Biosciences (CSTL) Shares Outstanding (2018 - 2026) Analysis & Trends
For FY2025, Castle Biosciences' Shares Outstanding came in at 28.99 million, up 4.4% from FY2024.
- Annual Shares Outstanding has increased for seven consecutive years, with a five-year compound annual growth rate of 8.9% (FY2020 to FY2025).
- In prior years, Castle Biosciences' Shares Outstanding was 27.78 million in FY2024 (+3.6%), 26.8 million in FY2023 (+2.9%), 26.05 million in FY2022 (+3.6%) and 25.14 million in FY2021 (+32.8%).
- The Q2 2026 figure stands as the highest quarterly Shares Outstanding in data going back to Q2 2018.
- On a year-over-year basis, Shares Outstanding has increased in each of the last 29 quarters, with growth averaging 4.3% over the last eight quarters.
- Across the past five years, year-over-year growth in Shares Outstanding ran from 2.0% in Q3 2023 to 32.8% in Q4 2021.
- According to Business Quant data, Shares Outstanding for the three prior quarters was 29.89 million (Q1 2026), 28.99 million (Q4 2025) and 29.07 million (Q3 2025).
Peer Set
Peer Comparison
| # | Company | Market Cap | Enterprise Value | Gross Profit (Qtr) | Shares Outstanding (Qtr) |
|---|---|---|---|---|---|
| 1 | HCA Healthcare | 101.26 Bn | 97.27 Bn | - | 220.54 Mn |
| 2 | Natera | 55.27 Bn | 50.95 Bn | 485.19 Mn | 143.28 Mn |
| 3 | Labcorp Holdings | 26.34 Bn | 24.09 Bn | 1.11 Bn | 81.70 Mn |
| 4 | Quest Diagnostics | 25.89 Bn | 24.02 Bn | 1.03 Bn | 111.00 Mn |
| 5 | Tenet Healthcare | 22.20 Bn | 11.20 Bn | - | 83.52 Mn |
| 6 | Guardant Health | 21.13 Bn | 17.19 Bn | 219.03 Mn | 132.87 Mn |
| 7 | Fresenius Medical Care AG | 12.80 Bn | 4.75 Bn | 1.52 Bn | 582.38 Mn |
| 8 | BrightSpring Health Services | 12.36 Bn | 10.70 Bn | 492.75 Mn | 206.04 Mn |
| 9 | Encompass Health | 12.08 Bn | 11.74 Bn | - | 98.80 Mn |
| 10 | Castle Biosciences | 1.01 Bn | -105.79 Mn | 79.85 Mn | 30.40 Mn |
Historic Data
Download Data
Historic Data
| Date | Value |
|---|---|
| Jun 30, 2026 | 30.40 Mn |
| Mar 31, 2026 | 29.89 Mn |
| Dec 31, 2025 | 28.99 Mn |
| Sep 30, 2025 | 29.07 Mn |
| Jun 30, 2025 | 28.91 Mn |
| Mar 31, 2025 | 28.61 Mn |
| Dec 31, 2024 | 27.78 Mn |
| Sep 30, 2024 | 27.84 Mn |
| Jun 30, 2024 | 27.65 Mn |
| Mar 31, 2024 | 27.49 Mn |
| Dec 31, 2023 | 26.80 Mn |
| Sep 30, 2023 | 26.83 Mn |
| Jun 30, 2023 | 26.73 Mn |
| Mar 31, 2023 | 26.61 Mn |
| Dec 31, 2022 | 26.05 Mn |
| Sep 30, 2022 | 26.32 Mn |
| Jun 30, 2022 | 26.06 Mn |
| Mar 31, 2022 | 25.42 Mn |
| Dec 31, 2021 | 25.14 Mn |
| Sep 30, 2021 | 25.29 Mn |
API Access
Castle Biosciences Shares Outstanding API
Pull this series into your own models, spreadsheets and apps with the Business Quant
Historical Metrics API. The request below matches the chart above — change the
frequency, period or values and it follows. Swap YOUR_API_KEY for your own key.
https://data.businessquant.com/historic?slug=shares-outstanding&ticker=CSTL&period=max&api_key=YOUR_API_KEYimport requests
url = "https://data.businessquant.com/historic"
params = {"slug": "shares-outstanding", "ticker": "CSTL", "period": "max", "api_key": "YOUR_API_KEY"}
data = requests.get(url, params=params).json()const res = await fetch("https://data.businessquant.com/historic?slug=shares-outstanding&ticker=CSTL&period=max&api_key=YOUR_API_KEY");
const data = await res.json();