As of today (2026-06-25), Castle Biosciences's share price is $22.12. Castle Biosciences's GF Value is $29.15. Therefore, Castle Biosciences's Price-to-GF-Value for today is 0.76. Based on the relationship between the current stock price and the GF Value, GuruFocus believes Castle Biosciences is Modestly Undervalued.
The GF Value represents the intrinsic value of a stock, determined using GuruFocus' proprietary methodology. The GF Value Line on our stock Summary page provides an estimate of the stock’s fair-trading value.
To calculate this value, GuruFocus follows these steps:
We analyze historical correlations between the stock price and key business performance metrics, such as revenue, earnings, cash flow, and book value.
We identify the metrics that have the strongest historical correlation with the stock price and determine the historical multiples at which the stock has traded relative to these metrics.
Using these historical multiples as a reference, we estimate the stock's fair value while accounting for future business growth. Adjustments may be made based on the company’s past returns and growth trends.
GuruFocus believes that the GF Value Line represents the fair value at which a stock should trade. Stock prices typically fluctuate around this line. If a stock’s price is significantly above the GF Value Line, it is considered overvalued, and its future returns are likely to be lower. Conversely, if the stock price is significantly below the GF Value Line, its future returns are likely to be higher.
Castle Biosciences (NAS:CSTL) GF Value Explanation
Based on the relationship between the current stock price and the GF Value, GuruFocus provides the following 6 ratings:
(1) These are some simple examples. You can access our GF Valuation filter under All-in-One Screener’s Fundamental tab, and Price-to-GF-Value filter under Valuation Ratio tab and set your own criteria.
(2) A sufficient margin of safety exists only when the stock is undervalued.
Possible Value Trap, Think Twice companies are those that appear significantly undervalued based on their Price-to-GF-Value ratio, but whose fundamentals show signs of weakness.
Indicators that a company may be a value trap include:
* Deteriorating Financial Health: A low Altman Z-scores indicates a higher risk of bankruptcy, or a low Piotroski F-Score. * Earnings Manipulation: A high Beneish M-score indicates potential earnings manipulation, raising concerns about the reliability of reported financials. * Stagnant or Declining Growth: Lack of revenue or earnings growth, or a recent slowdown, may signal limited future prospects.
Investors should conduct thorough due diligence, examining financial statements and growth indicators, to avoid falling into value traps.
Castle Biosciences's Price-to-GF-Value for today is calculated as
Price-to-GF-Value
=
Share Price
/
GF Value
=
22.12
/
29.15
=
0.76
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
Castle Biosciences (CSTL) has a GF Value of $29.15 as of Jun. 25, 2026. GF Value represents the current intrinsic value of a stock derived from our exclusive method. View historical data on Castle Biosciences and its competitors.
Is Castle Biosciences' GF Value too high?
Castle Biosciences' current GF Value is $29.15. Overall, Castle Biosciences has a GF Score™ of 70/100 and is considered Modestly Undervalued, reflecting its overall financial health beyond just this single metric.
How does Castle Biosciences' GF Value compare to FLGT and MYGN?
Castle Biosciences' GF Value of $29.15 can be compared against companies in the Medical Diagnostics & Research industry. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good GF Value for a Medical Diagnostics & Research company?
A good GF Value depends on the Medical Diagnostics & Research industry context. However, GF Value should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high GF Value mean?
A high GF Value can signal that a stock is expensive relative to its fundamentals. GF Value represents the current intrinsic value of a stock derived from our exclusive method. View historical data on Castle Biosciences and its competitors. Castle Biosciences's current GF Value is $29.15. However, context matters — high-growth companies often justify higher valuations. Always evaluate alongside other metrics like GF Score™ and GF Value™.
Is Castle Biosciences stock overvalued right now?
Based on GuruFocus' analysis, Castle Biosciences (CSTL) is currently considered Modestly Undervalued. The stock's GF Value™ is $29.15, compared to a current price of $22.12 — trading 24.1% below its estimated fair value. The current GF Value is $29.15. Castle Biosciences' overall GF Score™ is 70/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is GF Value calculated?
GF Value is calculated from a company's financial statements. For Castle Biosciences (CSTL), the current GF Value is $29.15 as of Jun. 25, 2026. GuruFocus calculates this using data sourced from SEC filings and annual reports. See the calculation section and 30-year financial data on this page for the full breakdown.
Is Castle Biosciences (CSTL) Overvalued in 2026?
Based on GuruFocus' analysis, Castle Biosciences stock appears to be undervalued.
The current stock price of $22.12 is trading 24.1% below its estimated GF Value™ of $29.15.
GuruFocus considers Castle Biosciences to be Modestly Undervalued.
Key valuation signals for CSTL:
GF Value: $29.15
GF Value™: $29.15 vs. price of $22.12 (24.1% below fair value)
No single metric tells the full story. See the CSTL stock analysis page for a complete view including 30-year financials, guru trades, and insider activity.
Castle Biosciences Inc is a molecular diagnostics company. The group provides test solutions for the diagnosis and treatment of dermatologic cancers, Barrett's esophagus (BE), and uveal melanoma. The product portfolio of the company includes DecisionDx-Melanoma, a risk stratification gene expression profile (GEP) test; DecisionDx-SCC, a risk stratification test for cutaneous squamous cell carcinoma; MyPath Melanoma, a diagnostic GEP test for use in patients with difficult-to-diagnose melanocytic lesions; and TissueCypher, a test to predict future development of progression of high-grade dysplasia and/or esophageal cancer. The company derives revenues through the delivery of test reports for its molecular diagnostic tests.
70GF Score
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