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Castle BiosciencesCSTL -3.16%79 Debt-to-Equity is 0.08 as of Mar. 2026, which is 33% above its 10-year median of 0.06. GuruFocus rates CSTL with a GF Score™ of 79/100 and a GF Value™ of $29.22 (Modestly Undervalued). The stock has 4 warning signs investors should review. Among 183 Medical Diagnostics & Research companies, Castle Biosciences ranks better than 80.87% on this metric.
A high debt to equity ratio generally means that a company has been aggressive in financing its growth with debt. This can result in volatile earnings as a result of the additional interest expense.
The historical rank and industry rank for Castle Biosciences's Debt-to-Equity or its related term are showing as below:
CSTL'
s Debt-to-Equity Range Over the Past 10 Years
Min: -8.1 Med: 0.06 Max: 11.81
Current: 0.08
During the past 9 years, the highest Debt-to-Equity Ratio of Castle Biosciences was 11.81. The lowest was -8.10. And the median was 0.06.
CSTL's Debt-to-Equity is ranked better than 80.87% of 183
companies
in the Medical Diagnostics & Research industry
Industry Median: 0.33
vs CSTL: 0.08
Because a company can increase its ROE % by having more financial leverage, it is important to watch the leverage ratio when investing in high ROE % companies.
Castle Biosciences Debt-to-Equity Related Terms
Castle Biosciences Debt-to-Equity Historical Data
* Premium members only.
The historical data trend for Castle Biosciences's Debt-to-Equity 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.
CSTL vs FLGT, MYGN, OPK: Debt-to-Equity Comparison
For the Diagnostics & Research subindustry, Castle Biosciences's Debt-to-Equity, along with its competitors' market caps and Debt-to-Equity 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 Debt-to-Equity vs Medical Diagnostics & Research Industry
For the Medical Diagnostics & Research industry and Healthcare sector, Castle Biosciences's Debt-to-Equity distribution charts can be found below:
* The bar in red indicates where Castle Biosciences's Debt-to-Equity 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 Debt-to-Equity of 0.08 as of Mar. 2026. Debt-to-Equity ratio represents the ratio of total debt to total company equity. View historical data on Castle Biosciences and its competitors. This is 33% above median its historical median of 0.06. According to the industry distribution chart, Castle Biosciences ranks #35 out of 183 companies in the Medical Diagnostics & Research industry, placing it in the top 19.1%.
Is Castle Biosciences' Debt-to-Equity too high?
Castle Biosciences' current Debt-to-Equity of 0.08 is 33% above median its 10-year median of 0.06. The Medical Diagnostics & Research industry median Debt-to-Equity is 0.33. Castle Biosciences' value of 0.08 is 75.8% below this industry median. Based on the distribution chart, Castle Biosciences ranks #35 out of 183 companies in the Medical Diagnostics & Research industry, which is in the top quartile — a strong position relative to peers. Overall, Castle Biosciences has a GF Score™ of 79/100 and is considered Modestly Undervalued, reflecting its overall financial health beyond just this single metric.
How does Castle Biosciences' Debt-to-Equity compare to FLGT and MYGN?
According to the Medical Diagnostics & Research industry distribution chart, Castle Biosciences ranks #35 out of 183 companies for Debt-to-Equity. This places Castle Biosciences in the top 19% of its industry — outperforming the majority of peers. The industry median Debt-to-Equity is 0.33. Castle Biosciences' value of 0.08 is 75.8% below this benchmark. While the company's 10-year median is 0.06 vs. the industry median of 0.33, Castle Biosciences has consistently been below the industry average. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good Debt-to-Equity for a Medical Diagnostics & Research company?
The median Debt-to-Equity among Medical Diagnostics & Research companies is 0.33, based on 183 companies in the industry. Companies in the top quartile (top 25%) have a Debt-to-Equity significantly above this median, while those in the bottom quartile fall well below. However, Debt-to-Equity should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Castle Biosciences's current Debt-to-Equity of 0.08 is 75.8% below the industry median. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high Debt-to-Equity mean?
A high Debt-to-Equity can signal that a stock is expensive relative to its fundamentals. Debt-to-Equity ratio represents the ratio of total debt to total company equity. View historical data on Castle Biosciences and its competitors. For the Medical Diagnostics & Research industry, the median Debt-to-Equity is 0.33 — values significantly above this may indicate overvaluation, while values below may suggest a bargain or underlying issues. Castle Biosciences's current Debt-to-Equity is 0.08, which is 33% above median its own 10-year median of 0.06. 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 $29.22, compared to a current price of $24.69 — trading 15.5% below its estimated fair value. The current Debt-to-Equity is 0.08, which is 33% above median its 10-year median of 0.06 and 75.8% below the Medical Diagnostics & Research industry median of 0.33. Castle Biosciences' overall GF Score™ is 79/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is Debt-to-Equity calculated?
Debt-to-Equity is calculated from a company's financial statements. For Castle Biosciences (CSTL), the current Debt-to-Equity is 0.08 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 $24.69 is trading 15.5% below its estimated GF Value™ of $29.22.
GuruFocus considers Castle Biosciences to be Modestly Undervalued.
Key valuation signals for CSTL:
Debt-to-Equity: 0.08 (33% above median its 10-year median of 0.06)
GF Value™: $29.22 vs. price of $24.69 (15.5% below fair value)
Industry Position: 75.8% below the Medical Diagnostics & Research median (#35 of 183)
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.
79GF Score
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