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Dr. Charlie Tian is the founder and CEO of GuruFocus.com, a leading global investment research platform established in 2004. With a Ph.D. in physics, Dr. Tian transitioned from science to finance, applying a data-driven, disciplined approach to value investing.
Castle BiosciencesCSTL +0.57%77 Graham Number is $N/A as of Mar. 2026. GuruFocus rates CSTL with a GF Score™ of 77/100 and a GF Value™ of $29.20 (Modestly Undervalued). The stock has 4 warning signs investors should review. Among 71 Medical Diagnostics & Research companies, Castle Biosciences ranks worse than 1408449.3% on this metric.
Graham Number is a figure that measures a stock's fundamental value by taking into account the company's earnings per share and book value per share. The Graham number is the upper bound of the price range that a defensive investor should pay for the stock. According to the theory, any stock price below the Graham number is considered undervalued, and thus worth investing in.
As of today (2026-07-15), the stock price of Castle Biosciences is $23.13. Castle Biosciences's graham number for the quarter that ended in Mar. 2026 was $N/A. Therefore, Castle Biosciences's Price to Graham Number ratio for today is N/A.
The historical rank and industry rank for Castle Biosciences's Graham Number or its related term are showing as below:
During the past 9 years, the highest Price to Graham Number ratio of Castle Biosciences was 3.82. The lowest was 1.67. And the median was 2.06.
CSTL's Price-to-Graham-Number is not ranked *
in the Medical Diagnostics & Research industry.
Industry Median: 2.59 * Ranked among companies with meaningful Price-to-Graham-Number only.
Graham Number is a combination of asset valuation and earnings power valuation. It is a very conservative way of valuing a stock.
Castle Biosciences (NAS:CSTL) Graham Number Explanation
Ben Graham actually did not publish a formula like this. But he wrote in The Intelligent Investor (1948 version) regarding to the criteria for purchases:
Current price should not be more than 15 times average earnings of the past three years.
Current price should not be more than 1.5 times the book value last reported. However, a multiplier of earnings below 15 could justify a correspondingly higher multiplier of assets. As a rule of thumb we suggest that the product of the multiplier times the ratio of price to book value should not exceed 22.5. (This figure corresponds to 15 times earnings and 1.5 times book value. It would admit an issue selling at only 9 times earnings and 2.5 times asset value, etc.)
Unlike valuation methods such as DCF or Discounted Earnings, the Graham number does not take growth into the valuation. Unlike the valuation methods based on book value alone, it takes into account the earnings power. Therefore, the Graham Number is a combination of asset valuation and earnings power valuation.
In general, the Graham number is a very conservative way of valuing a stock. It cannot be applied to companies with negative book values.
Castle Biosciences's Price to Graham number Ratio for today is calculated as
Price to Graham number
=
Share Price (Today)
/
Graham number (Q: Mar. 2026 )
=
23.13
/
N/A
=
N/A
* 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.
Be Aware
Please keep these in mind:
1. Graham Number does not take growth into account. Therefore it underestimates the values of the companies that have good earnings growth. We feel that if the earnings per share grows more than 10% a year, Graham Number underestimates the value.
2. Graham Number punishes the companies that have temporarily low earnings. Therefore, an average of earnings makes more sense in the calculation of Graham Number.
3. Graham Numbers underestimates companies that are light with book.
Castle Biosciences Graham Number Related Terms
Castle Biosciences Graham Number Historical Data
* Premium members only.
The historical data trend for Castle Biosciences's Graham Number can be seen below:
* 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.
For the Diagnostics & Research subindustry, Castle Biosciences's Price-to-Graham-Number, along with its competitors' market caps and Price-to-Graham-Number data, can be viewed below:
* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.
Castle Biosciences Price-to-Graham-Number vs Medical Diagnostics & Research Industry
For the Medical Diagnostics & Research industry and Healthcare sector, Castle Biosciences's Price-to-Graham-Number distribution charts can be found below:
* The bar in red indicates where Castle Biosciences's Price-to-Graham-Number falls into.
* 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 Graham Number of $N/A as of Mar. 2026. The Graham Number values a company based on its per-share earnings and book value. View historical data on Castle Biosciences and its competitors. Over the past decade, Castle Biosciences' Graham Number has ranged from 1.67 to 3.82. According to the industry distribution chart, Castle Biosciences ranks #999999 out of 71 companies in the Medical Diagnostics & Research industry.
Is Castle Biosciences' Graham Number too high?
Castle Biosciences' current Graham Number is $N/A. Over the past 10 years, this metric has ranged from a low of 1.67 to a high of 3.82. Based on the distribution chart, Castle Biosciences ranks #999999 out of 71 companies in the Medical Diagnostics & Research industry, which is in the bottom quartile relative to peers. Overall, Castle Biosciences has a GF Score™ of 77/100 and is considered Modestly Undervalued, reflecting its overall financial health beyond just this single metric.
How does Castle Biosciences' Graham Number compare to FLGT and MYGN?
According to the Medical Diagnostics & Research industry distribution chart, Castle Biosciences ranks #999999 out of 71 companies for Graham Number. This places Castle Biosciences in the lower half of its industry. The industry median Graham Number is 2.59. Historically, Castle Biosciences' own Graham Number has ranged from 1.67 to 3.82 over the past decade. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good Graham Number for a Medical Diagnostics & Research company?
The median Graham Number among Medical Diagnostics & Research companies is 2.59, based on 71 companies in the industry. Companies in the top quartile (top 25%) have a Graham Number significantly above this median, while those in the bottom quartile fall well below. However, Graham Number 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 Graham Number mean?
A high Graham Number can signal that a stock is expensive relative to its fundamentals. The Graham Number values a company based on its per-share earnings and book value. View historical data on Castle Biosciences and its competitors. For the Medical Diagnostics & Research industry, the median Graham Number is 2.59 — values significantly above this may indicate overvaluation, while values below may suggest a bargain or underlying issues. Castle Biosciences's current Graham Number is $N/A. 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 $29.20, compared to a current price of $23.13 — trading 20.8% below its estimated fair value. The current Graham Number is $N/A. Castle Biosciences' overall GF Score™ is 77/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is Graham Number calculated?
Graham Number is calculated from a company's financial statements. For Castle Biosciences (CSTL), the current Graham Number is $N/A as of Mar. 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 $23.13 is trading 20.8% below its estimated GF Value™ of $29.20.
GuruFocus considers Castle Biosciences to be Modestly Undervalued.
Key valuation signals for CSTL:
Graham Number: $N/A
GF Value™: $29.20 vs. price of $23.13 (20.8% 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.
77GF Score
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