Latest Ratios: P/E Ratio -43.3x · EV/EBITDA N/A · ROE -5.2%. (2017–2025 historical series)
Price-based multiples — how expensive the stock is relative to earnings, sales, book value, and cash flow
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Market Cap | $986M | $1.1B | $780M | $578M | $613M | $1.1B | $1.3B | $298M | — | — |
| Enterprise Value | $907M | $1.0B | $686M | $495M | $504M | $756M | $861M | $224M | — | — |
| P/E Ratio → | -43.28 | — | 42.98 | — | — | — | — | — | — | — |
| P/S Ratio | 2.62 | 3.28 | 2.35 | 2.63 | 4.48 | 11.45 | 20.29 | 5.74 | — | — |
| P/B Ratio | 2.00 | 2.39 | 1.71 | 1.48 | 1.54 | 2.62 | 3.06 | 3.50 | — | — |
| P/FCF | 248.88 | 39.81 | 21.34 | — | — | — | 248.55 | 48.96 | — | — |
| P/OCF | 15.33 | 17.52 | 12.02 | — | — | — | 128.85 | 42.42 | — | — |
P/E links to full P/E history page with 30-year chart
Enterprise-value multiples — capital-structure-neutral measures of total business value
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| EV / Revenue | — | 3.04 | 2.07 | 2.25 | 3.68 | 8.04 | 13.75 | 4.32 | — | — |
| EV / EBITDA | — | — | 27.82 | — | — | — | — | 29.12 | — | — |
| EV / EBIT | — | — | 31.00 | — | — | — | — | 22.57 | — | — |
| EV / FCF | — | 36.99 | 18.78 | — | — | — | 168.41 | 36.83 | — | — |
Margins and return-on-capital ratios measuring operating efficiency
Full margin charts and quarterly trend are on the Earnings History page
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Gross Margin | 79.4% | 79.4% | 81.9% | 79.5% | 76.6% | 83.2% | 84.5% | 85.9% | 76.8% | 64.2% |
| Operating Margin | -12.4% | -12.4% | 2.6% | -30.9% | -53.2% | -42.6% | -10.4% | 14.1% | -16.8% | -79.2% |
| Net Profit Margin | -7.0% | -7.0% | 5.5% | -26.1% | -49.0% | -33.3% | -16.4% | 10.2% | -27.9% | -89.9% |
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| ROE | -5.2% | -5.2% | 4.3% | -14.5% | -16.6% | -7.6% | -4.1% | 14.1% | — | — |
| ROA | -4.4% | -4.4% | 3.7% | -12.8% | -14.8% | -6.9% | -3.7% | 7.4% | -39.5% | -126.0% |
| ROIC | -8.5% | -8.5% | 1.9% | -17.1% | -28.8% | -62.5% | -57.0% | 51.5% | -44.0% | -262.1% |
| ROCE | -8.6% | -8.6% | 2.0% | -16.6% | -17.2% | -9.4% | -2.5% | 12.2% | -37.9% | -237.0% |
Solvency and debt-coverage ratios — lower is generally safer
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Debt / Equity | 0.08 | 0.08 | 0.06 | 0.04 | 0.03 | 0.02 | — | 0.30 | — | — |
| Debt / EBITDA | — | — | 1.07 | — | — | — | — | 3.27 | — | — |
| Net Debt / Equity | — | -0.17 | -0.20 | -0.21 | -0.27 | -0.78 | -0.99 | -0.87 | — | — |
| Net Debt / EBITDA | — | — | -3.79 | — | — | — | — | -9.59 | — | — |
| Debt / FCF | — | -2.82 | -2.56 | — | — | — | -80.14 | -12.13 | — | — |
| Interest Coverage | -342.19 | -342.19 | 38.37 | -5214.00 | -4052.18 | -40011.00 | -2.87 | 2.17 | -1.80 | -6.49 |
Net cash position: cash ($117M) exceeds total debt ($37M)
Short-term solvency ratios and asset-utilisation metrics
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Current Ratio | 5.26 | 5.26 | 7.29 | 6.20 | 8.09 | 14.21 | 20.58 | 7.63 | 2.69 | 1.28 |
| Quick Ratio | 5.11 | 5.11 | 7.13 | 6.04 | 7.98 | 14.13 | 20.47 | 7.55 | 2.56 | 1.22 |
| Cash Ratio | 4.36 | 4.36 | 5.93 | 5.10 | 7.16 | 13.25 | 19.63 | 6.47 | 0.66 | 0.23 |
| Asset Turnover | — | 0.59 | 0.63 | 0.48 | 0.31 | 0.20 | 0.14 | 0.43 | 1.02 | 1.40 |
| Inventory Turnover | 6.93 | 6.93 | 7.40 | 5.66 | 8.04 | 7.83 | 4.37 | 5.91 | 6.00 | 16.16 |
| Days Sales Outstanding | — | 46.00 | 56.30 | 63.61 | 62.53 | 67.05 | 74.34 | 103.09 | 193.67 | 123.46 |
Earnings, FCF, buyback, and dividend yields — total returns to shareholders
Full dividend history and growth charts are on the Dividend History page
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Dividend Yield | — | — | — | — | — | — | — | — | — | — |
| Payout Ratio | — | — | — | — | — | — | — | — | — | — |
| Metric | TTM | FY 2025 | FY 2024 | FY 2023 | FY 2022 | FY 2021 | FY 2020 | FY 2019 | FY 2018 | FY 2017 |
|---|---|---|---|---|---|---|---|---|---|---|
| Earnings Yield | — | — | 2.3% | — | — | — | — | — | — | — |
| FCF Yield | 0.4% | 2.5% | 4.7% | — | — | — | 0.4% | 2.0% | — | — |
| Buyback Yield | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | — | — |
| Total Shareholder Yield | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | — | — |
| Shares Outstanding | — | $29M | $29M | $27M | $26M | $25M | $19M | $9M | $11M | $10M |
Includes 30+ ratios · 9 years · Updated daily
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Compare growth, multiples, and margins vs sector.
Quick answers to the most common questions about buying CSTL stock.
Castle Biosciences, Inc.'s current P/E ratio is -43.3x. The historical average is 43.0x.
Castle Biosciences, Inc.'s return on equity (ROE) is -5.2%. The historical average is -4.2%.
Based on historical data, Castle Biosciences, Inc. is trading at a P/E of -43.3x. Compare with industry peers and growth rates for a complete picture.
Castle Biosciences, Inc. has 79.4% gross margin and -12.4% operating margin.
Key Metrics
Top Statement Risk
Medicare LCD uncertainty for SCC
Metrics are mathematically derived from official filings.
Gross Margin Erosion Amid Expansion
Gross margin slipped from 83.3% in Q2 2024 to 77.1% in Q2 2026, per financial statements, suggesting pricing pressure or mix shift. Operating margin improved to -3.0% from -22.0% sequentially, indicating leverage.
The 620 basis point decline in gross margin over eight quarters likely reflects a combination of reimbursement pressure and a changing product mix as newer tests like TissueCypher scale. Despite this, the sequential operating margin improvement from -22.0% to -3.0% suggests that SG&A growth is moderating relative to revenue, a sign that the heavy investment phase may be maturing. Investors should monitor whether gross margin stabilizes, as further erosion could offset the benefits of operating leverage.
Returns Trapped in Investment Phase
ROIC has hovered near zero, turning slightly positive in 2024 quarters but negative in 2026, as reported. The 0.19 asset turnover in Q2 2026 reflects a capital-intensive build-out, with returns yet to materialize.
ROIC oscillated between -5.7% and +1.1% over the past ten quarters, indicating that the company is not yet generating consistent returns on its invested capital. The increase in PP&E from $44.9M to $118.9M over the period, per balance sheet data, shows heavy investment in lab infrastructure, which has yet to translate into profitability. This pattern is typical for a growth-stage diagnostics company, but the lack of improvement in ROIC despite revenue growth suggests that capital efficiency is not yet a strength.
Working Capital Efficiency Improves
Cash conversion cycle shortened to 33 days in Q2 2026 from 57 days in Q4 2024, per reported figures, driven by faster collections and extended payables. DSO fell to 40 days, while DPO rose to 47 days.
The improvement in CCC reflects better working capital management, with DSO declining from 54 to 40 days and DPO increasing from 39 to 47 days over the same period. This suggests that CSTL is collecting receivables more quickly and stretching payables, which is a positive sign for cash flow. However, the volatility in CCC, swinging from 17 to 57 days, indicates that working capital is sensitive to billing cycles and payer mix, warranting close monitoring.
Minimal Debt, Ample Headroom
Debt-to-equity remains low at 0.08, with total debt stable at $36.6M, as reported. Interest coverage is negative due to losses, but the cash position of $62.1M provides a buffer.
CSTL's leverage is minimal, with a D/E ratio of 0.08 and no significant debt maturities, reducing refinancing risk. The negative interest coverage ratios reflect the company's unprofitable status, but the low absolute debt level means that interest expense is not a material burden. The $62.1M cash balance, combined with the $116M cash position noted earlier, suggests that the company has sufficient liquidity to fund operations without immediate need for external financing.
Liquidity Cushion Remains Strong
Current ratio stands at 6.04 in Q2 2026, down from 9.25 in Q1 2024, per financial statements, but still robust. Quick ratio of 5.85 indicates minimal inventory dependence, with ample cash to cover short-term obligations.
The current ratio has declined from 9.25 to 6.04 over the past two years, reflecting increased investment in PP&E and other long-term assets, but it remains well above the 2.0 threshold typically considered healthy. The quick ratio of 5.85 confirms that the company does not rely on inventory to meet obligations, which is consistent with a service-based diagnostics model. Even under a severe stress scenario, such as a negative LCD decision, the liquidity position appears sufficient to weather a temporary revenue disruption.
P/S Misleads on Platform Value
The price-to-sales ratio of 2.68 appears reasonable for a growth diagnostics firm, but it obscures the high fixed-cost structure and reimbursement risk. A more appropriate metric is EV/EBITDA, which is negative due to losses.
P/S is commonly used for early-stage companies, but for CSTL it fails to capture the significant operating leverage and the potential for margin expansion as revenue scales. The negative EV/EBITDA (due to negative EBITDA) makes the metric unusable, so investors should focus on gross margin trends and the path to operating break-even. Additionally, the market's focus on P/S may understate the impact of a negative Medicare LCD decision, which could disproportionately affect revenue and margins. A better approach is to model revenue under different reimbursement scenarios and apply a discounted cash flow analysis.