CASTLE BIOSCIENCES INC (CSTL)
Health Care · Molecular Diagnostics · NASDAQ
Castle Biosciences is a molecular diagnostics company offering gene expression profile tests to improve management of dermatologic and gastrointestinal cancers.
What CASTLE BIOSCIENCES INC does
Castle Biosciences is a diagnostics company focused on providing prognostic and predictive tests for dermatologic and gastroenterologic cancers. The company utilizes proprietary gene expression profile (GEP) and other technologies to help clinicians make more informed treatment decisions. Its test portfolio assists in managing conditions such as cutaneous melanoma, squamous cell carcinoma, and Barrett’s esophagus.
Themes: precision medicine, oncology diagnostics, dermatology, gastroenterology, molecular testing
Fundamentals
- Price$34.20 as of 2026-08-21 close
- Market cap$1.0B as of 2026-08-21
- 1-year return+71.3% 2025-08-21 close $19.97 → 2026-08-21 close $34.20
- P/En/a negative earnings
- Net margin-5.4% as of 2026-08-24
- Gross margin+77.3% as of 2026-08-24
- ROE-4.2% as of 2026-08-24
- Debt / equity0.02 as of 2026-08-24
- Revenue growth (YoY)+3.2% as of 2026-08-24
- Revenue CAGR (3y)+35.9% SEC XBRL
- Beta0.99 as of 2026-08-24
- Last reported earnings2026-07-30 SEC EDGAR Form 8-K (Item 2.02)
How CSTL compares in its sector
- net profit marginmiddle range 504 covered Health Care peers, as of 2026-08-24
- operating marginmiddle range 504 covered Health Care peers, as of 2026-08-24
- gross marginmiddle range 384 covered Health Care peers, as of 2026-08-24
- return on equitymiddle range 576 covered Health Care peers, as of 2026-08-24
- 3-year revenue CAGRtop 25% 402 covered Health Care peers
- free cash flow (absolute dollars, latest fiscal year)middle range 493 covered Health Care peers, as of FY2025
Position among covered Health Care companies that report each metric (minimum 5 peers). A relative position within our covered catalog — not a valuation, quality, or investment judgment. A higher percentile is simply a higher value (for P/E, more expensive on earnings — never "better"). Informational only.
How CASTLE BIOSCIENCES INC looks technically
CASTLE BIOSCIENCES INC (CSTL) is trading 16.0% above its 200-day average, the long-term trend line — a longer-term uptrend. Its 50-day average crossed below its 200-day average about 87 trading days ago — a "death cross", a bearish long-term signal. A strong uptrend is in place — ADX, a 0–100 trend-strength gauge, is 43, with buyers in control. Momentum is stretched — its 14-day RSI (a 0–100 momentum gauge) is 71, in overbought territory (above 70). MACD, a trend-momentum gauge, turned bullish about 1 trading day ago (its momentum flipped positive). It just made a new 20-day high, its first since 2026-02-04, pushing above its recent trading range. It is 22.8% below its highest point of the past year.
Trend
9
| Distance from the 200-day | it is trading 16.0% above its 200-day average, the long-term trend line — a longer-term uptrend | +16.0% |
|---|---|---|
| 50-day moving average | its average price over the last 50 trading days — a short-term trend line — is $25.83 | $25.83 |
| 200-day moving average | its average price over the last 200 trading days — the long-term trend line — is $29.49 | $29.49 |
| Swing structure | each recent peak has been higher than the one before it and each dip has been shallower — the pattern chart-watchers call an uptrend, which describes where price has already been and not where it goes next | higher highs and higher lows |
| Last swing turn | its last significant turn was a swing high 11 calendar days ago — the swings before that are what the structure reading is measured on | 11 sessions |
| Wave structure | its recent swings can be read as a five-part upward sequence — what Elliott-wave chartists call an impulse — now in the fourth leg, a pullback against that upward direction; the labelling fails if price closes below 24.98. It is the only labelling that fits, and it describes the swings already printed, not what comes next. | possible upward five-wave sequence, in wave 4 |
| Since the 50/200 cross | its 50-day average crossed below its 200-day average about 87 trading days ago — a "death cross", a bearish long-term signal | 87 sessions |
| Above the 200-day after a dip | it recently dipped to its 200-day average (the long-term trend line) and has since climbed back above it — now about 16.0% above | +16.0% |
| Trend strength (14-day ADX) | a strong uptrend is in place — ADX, a 0–100 trend-strength gauge, is 43, with buyers in control | 43.3 |
Momentum
3
| 14-day RSI | momentum is stretched — its 14-day RSI (a 0–100 momentum gauge) is 71, in overbought territory (above 70) | 71.4 |
|---|---|---|
| Position in its 14-day range | it is trading near the top of its 14-day range ($28.72 to $34.70) — its "stochastic" reading is 92 out of 100, where 0 would mean closing exactly at the 14-session low and 100 exactly at the high. This measures WHERE the price sits inside its recent range, which is a different question from the RSI beside it: RSI is a momentum gauge, measuring how FAST the price has been moving, so a stock can drift quietly to the bottom of its range with an ordinary RSI, or fall sharply and still sit in the middle. It has been climbing within that range over the last few sessions. | 91.6 |
| Since the MACD crossed zero | MACD, a trend-momentum gauge, turned bullish about 1 trading day ago (its momentum flipped positive) | 1 session |
Range
12
| 52-week high | its highest closing price over the past year (about 252 trading days) was $44.28 | $44.28 |
|---|---|---|
| From the 52-week high | it is 22.8% below its 52-week high (its highest price of the past year) | -22.8% |
| Above the 52-week low | it is 93.0% above its 52-week low (its lowest price of the past year) | +93.0% |
| Below the 52-week high | it is 22.8% below its highest point of the past year | 22.8% |
| Since a 20-day breakout | it just made a new 20-day high, its first since 2026-02-04, pushing above its recent trading range | 1 session |
| Since a 55-day breakout | it just made a new 55-day high, its first since 2026-02-04, pushing above its recent trading range | 1 session |
| All-time high | its highest closing price on record is $107.69 (set on 2021-02-10) | $107.69 |
| Given back of the 52-week move | over the past year its closes ranged ($18.15 to $43.04), and it has recovered close to two thirds of its fall from last year’s high — 64% of it. Chart-watchers call 61.8%-65% given back the "golden pocket", and this is inside it — for this company that is $33.53 to $34.33. It is watched widely enough that orders cluster there, which is the honest reason it matters; it is not a forecast. | 64.5% |
| From the all-time high | it is 68.2% below its all-time high | -68.2% |
| Nearest price level | it is trading 0.8% below a resistance level at $34.47 — a price it turned at twice since 2024-10-15, most recently on 2026-02-18. Since 2024-08-21 it has 12 such levels below the current price and 3 above. Levels like these describe where the price has reversed or paused before; they are not a forecast of where it will go. | +0.8% |
| All-time low | its lowest closing price on record is $9.26 (set on 2023-06-05) | $9.26 |
| Above the all-time low | it is 269.3% above its all-time low | +269.3% |
Volatility
5
| Band width vs its own 6 months | day-to-day price swings are wider than usual versus its own recent 6-month history (wider than about 75% of it) | 75th percentile |
|---|---|---|
| Typical daily range | in a typical session it travels about $1.72 between its high and its low — about 5.0% of its price. That is its "average true range" over the last 14 sessions, which also counts the distance from the previous close, so a day that opens well away from yesterday counts as the large move it was | $1.72 |
| Bollinger bands (20-day, ±2σ) | most of its recent trading has stayed between about $24.10 and $35.57 — the "Bollinger bands", a range drawn two standard deviations either side of its 20-day average price, which widens when the stock gets more volatile and narrows when it settles | $24.10 – $29.83 – $35.57 |
| Typical daily range (% of price) | its price moves about 5.0% in a typical session — about typical for the companies we cover. This is the average gap between a session's high and low over the last 14 sessions, counting overnight moves, expressed against the current price so it can be compared with companies trading at any price | 5.0% |
| Stretch from the 200-day average | it is trading 2.7 daily ranges above its 200-day average price (16.0% above it in plain percentage terms) — a way of asking how far it has stretched from its own average in units of how far it normally moves in a day, so a calm company and a jumpy one can be compared on the same scale | 2.7 daily ranges above its 200-day average |
Volume
1
| Volume vs its 30-day average | trading volume is about normal versus its 30-day average | 1.29× |
|---|
Analyst
2
| Change in the average price target | analysts' average price target is unchanged from the prior reading | 0.0% |
|---|---|---|
| Change in the consensus rating | the analyst consensus rating is unchanged since the prior reading | unchanged |
Candlestick patterns
2
| Since a doji | 8 sessions ago it opened and closed at almost the same price after trading through a wider range — a "doji", the classic picture of buyers and sellers finishing the session level | 8 sessions ago |
|---|---|---|
| Since a bullish engulfing | 2 sessions ago it opened below the previous session's close and finished above that session's open — a "bullish engulfing" pair, where one up day more than undid the down day before it | 2 sessions ago |
Price gaps
3
| Gap at the open | it opened on 2026-08-21 0.2% below the previous session's close — an overnight gap, the part of the move that happened while the market was shut, and traded back through that level before the close | -0.2% |
|---|---|---|
| Open gap | it gapped 7.3% above the previous close 15 sessions ago and has not traded back through the level it left behind at 26.79 — an "unfilled gap", which describes a price range no trade has since crossed and is not a forecast that it will be crossed | +7.3% |
| Gap filled | a 4.7% gap up opened on 2026-06-11 has been "filled" 45 sessions ago — price traded back through the level the gap left behind, and it took 4 sessions to close | 45 sessions ago |
Price streaks
1
| Closing streak | it has closed higher 3 sessions in a row, a +17.81% move over the run — an unbroken run of up days, which describes what has already happened and says nothing about the next session | 3 sessions up |
|---|
Relative strength
4
| vs market, 1 month | over the past 1 month this stock beat the market by 37.2 percentage points (the stock gained 39.5% while the market gained 2.3%) | +37.2% |
|---|---|---|
| vs market, 3 months | over the past 3 months this stock beat the market by 63.4 percentage points (the stock gained 66.5% while the market gained 3.1%) | +63.4% |
| vs market, 6 months | over the past 6 months this stock beat the market by 6.0 percentage points (the stock gained 17.1% while the market gained 11.1%) | +6.0% |
| vs market, 12 months | over the past 12 months this stock beat the market by 50.8 percentage points (the stock gained 71.3% while the market gained 20.5%) | +50.8% |
Signal agreement
2
| Bullish technical signals | 6 of the 9 technical signals we can compute for it are currently in a bullish state: a strong uptrend, with buyers in control, trading above its 200-day average, a fresh 20-day high, MACD momentum is positive, outperforming the market over 6 months, trading above the Ichimoku cloud — these describe past price behaviour, not a forecast | 6 of 9 |
|---|---|---|
| Bearish technical signals | 3 of the 9 technical signals we can compute for it are currently in a bearish state: a "death cross" — its 50-day average is below its 200-day, its RSI momentum gauge is overbought (a stretched reading), near the top of its 14-day range (overbought) — these describe past price behaviour, not a forecast | 3 of 9 |
Trend (Ichimoku cloud)
1
| Vs the Ichimoku cloud | trading 48% above the Ichimoku cloud — a band drawn from where its own highs and lows sat up to 2026-07-16 and projected forward over today's price, the side traders read as an established uptrend, with the band below acting as the level that would have to give way. The band itself is moderate, spanning 4.2% of the share price. | +47.8% |
|---|
Volume-weighted price
2
| Vs this year’s average price paid | the price is 24% above the average price paid so far this year, so the typical buyer over that stretch is showing a gain. That average is $27.60 — a volume-weighted average of daily closes over 157 sessions, not a true tick-by-tick VWAP. | +23.9% |
|---|---|---|
| Vs the average paid since it last reported | the price is 13% above the average price paid since it last reported on 2026-07-30 (its 10-Q), so the typical buyer over that stretch is showing a gain. That average is $30.27 — a volume-weighted average of daily closes over 17 sessions, not a true tick-by-tick VWAP. | +13.0% |
Price levels it has turned at before
CSTL last closed at $34.20 on 2026-08-21. Since 2024-08-21 it has turned at 12 prices below its last close and 3 above; the 3 nearest below and the 3 nearest above are listed, nearest first.
| Level | Side | Distance | Evidence |
|---|---|---|---|
| $34.47 | Resistance | 0.8% above the last close | turned there twice · 2024-10-15 to 2026-02-18 |
| $35.66 | Resistance | 4.3% above the last close | turned there twice · 2024-11-05 to 2025-11-11 |
| $32.73 | Support | 4.3% below the last close | turned there four times · 2024-09-17 to 2026-08-10 |
| $30.88 | Support | 9.7% below the last close | turned there three times · 2024-08-30 to 2024-11-05 |
| $27.48 | Support | 19.6% below the last close | turned there three times · 2024-10-01 to 2024-11-19 |
| $42.03 | Resistance | 22.9% above the last close | turned there twice · 2025-12-22 to 2026-01-12 |
A level is a price this company reversed or paused at more than once — they describe past behaviour, not a forecast of where the price will go.
Wave structure
Its recent swings can be read as a five-part upward sequence — what Elliott-wave chartists call an impulse — now in leg 4 of five, a pullback against that direction.
This labelling fails — stops being a possible reading at all — if it closes below $24.98.
It is the only labelling that fits these swings, though its proportions are not the textbook ones.
On past moves of this shape the leg has usually ended somewhere between $27.76 and $30.56 — that is where it has tended to end if the count holds, not a forecast of where the price goes.
This reading has stood for 1 trading day, since 2026-08-21.
Read from daily closes as of 2026-08-21.
An Elliott-wave count describes the swings already printed and the level that would disprove it. It is not a forecast, a target, or advice.
Screens: Trading above the 200-day moving average · Tested and reclaimed 200-day support · Overbought (14-day RSI above 70) · Pulled back from the 12-month high · Broke out to a new 20-day high · MACD just crossed bullish (12/26/9) | Learn: moving average · golden cross · adx · rsi · macd · breakout · fifty two week high low
Based on daily closing prices as of 2026-08-21. Describes past price behavior only — informational, not financial advice.
Analyst consensus
- Consensus ratingStrong Buy (1.00 mean, 1=Strong Buy…5=Strong Sell) — 9 analysts
- Mean price target$44.00 range $35.00 – $57.00
Analyst estimates, as of 2026-08-19. These are third-party analyst opinions and price targets, aggregated — not a recommendation, prediction, or advice from stocks-llm. Informational only.
Analyst EPS estimate for CSTL
- Consensus EPS estimate-$0.3578 next reporting period, as of 2026-08-19
Change over time is not available yet: it needs two readings of the same reporting period at least 30 days apart, and we have been recording these estimates since 2026-08-04. An estimate for a DIFFERENT quarter is not a revision, so a reading from before the last report is never compared with one after it.
The consensus estimate for the next reporting period, and how it has moved between readings of that SAME period. A change is measured only between readings estimating one period — when a company reports, the consensus moves to the next quarter and the two numbers are not comparable. Informational only, not a forecast and not advice.
Key risks (from latest filing)
["History of operating losses and uncertainty regarding future profitability.","Significant reliance on the adoption and reimbursement of its proprietary diagnostic tests by third-party payers.","Intense competition in the molecular diagnostics industry and the risk of new diagnostic technologies rendering current products obsolete."]
What changed in the latest 10-Q
AI-assisted comparison of CSTL's 10-Q filed 2026-05-06 against the prior one filed 2025-11-03.
Management's Discussion & Analysis (MD&A)
- Added:
- Newer filing (2026-05-06) references 2025 10-K filed February 26, 2026; older filing (2025-11-03) references 2024 10-K filed February 27, 2025
- Newer filing adds description of atopic dermatitis (AD) in company overview
- Newer filing states six MAAA tests are currently offered; older filing states five are currently offered with a sixth planned for November 2025
- Newer filing notes AdvanceAD-Tx 'commenced a limited access launch' in November 2025; older filing states 'plan a limited access launch' of AdvanceAD-Tx in November 2025
- Newer filing adds reference to Capsulomics/Previse acquisition in May 2025 and Esopredict test offering
- Newer filing states Esopredict offered as supplemental option beginning Q1 2026
- Newer filing adds detail that AdvanceAD-Tx excludes from ADLT status reference ('excluding our recently launched AdvanceAD-Tx test')
- Newer filing modifies AdvanceAD-Tx TAM description: 'approximately 10 million individuals' vs older 'approximately 13.2 million individuals'
- Removed:
- Older filing references mental health test offering and IDgenetix PGx test; newer filing removes all reference to mental health test segment
- Older filing describes DecisionDx-Melanoma as predicting 'the risk of metastasis or recurrence, including a positive sentinel lymph node'; newer filing describes it as predicting 'the likelihood of a positive sentinel lymph node and the risk of metastasis or recurrence'
- Older filing references 'previously offered' mental health conditions test; newer filing removes this entirely
- Older filing describes TissueCypher as predicting 'progression of high-grade dysplasia'; newer filing describes as predicting 'future development of high-grade dysplasia'
- Older filing describes MyPath Melanoma for patients 'with a melanocytic lesion and uncertainty related to the malignancy'; newer filing describes as for 'difficult-to-diagnose melanocytic lesions'
- Older filing references MyPath Melanoma acquisition 'in May 2021'; newer filing removes historical acquisition reference
- Reworded:
- Forward-looking statements identifier list: newer adds 'could' and removes 'estimate' from opening list; newer adds 'or the negative or plural of these terms'
- MyPath Melanoma description: older states 'of the 2 million suspicious pigmented lesions biopsied annually'; newer specifies '2 million suspicious pigmented lesions biopsied annually in the U.S.'
- TissueCypher test description: older uses 'spatial omics' (two words); newer uses 'spatialomics' (one word)
- AdvanceAD-Tx pathway description: older states '12 known immune, inflammatory and skin-related pathways associated with inflammatory skin conditions'; newer states '12 known immune, inflammatory and skin-related pathways'
- DecisionDx-UM description: older states 'standard of care in the management of newly diagnosed UM in the majority of ocular oncology practices in the United States'; newer text is truncated but appears modified
- Notes:
- Newer filing MD&A text appears truncated at end of ophthalmology section
- Older filing text also appears truncated at mental health test section
- AdvanceAD-Tx TAM estimate change (13.2 million to 10 million) is factual but reason for change not provided in text
Risk Factors
The two filings could not be meaningfully compared for this section.
AI-assisted comparison of two SEC filing sections. It describes wording and theme changes only, makes no materiality, legal, or investment judgement, and is not financial advice. Informational only — not financial advice.
Insider activity (SEC Form 4)
0 open-market purchases and 58 open-market sales by insiders in the last 90 days.
- Last 30 days0 buys · 27 sells ($2M) — 3 selling insiders
- Last 90 days0 buys · 58 sells ($3M) — 3 selling insiders
- Last 180 days0 buys · 100 sells ($4M) — 3 selling insiders
Activity heuristic: net selling (a transparent product heuristic from the counts above, not a prediction or advice)
Most recent open-market transaction: 2026-08-03. As of 2026-08-24.
View full insider trading history → View SEC Form 3/4/5 filingsAsk about CSTL's insider activity →
Only open-market purchases (SEC code P) and sales (code S) are counted here. Option exercises, vesting/awards, gifts, and shares withheld for taxes are excluded — they are compensation or mechanical, not open-market conviction. Sales may be planned and non-discretionary (e.g. a Rule 10b5-1 plan) and are not necessarily bearish; open-market buying is not a recommendation to buy. Informational only — not financial advice.
Institutional ownership (13F)
5 institutional 13F filers reported holding CSTL as of 2026-03-31 (quarter-end position, filed within 45 days).
- Distinct 13F filers 5
- Reported shares held 4,501,214
- Reported value $110,504,801
reported quarterly holdings change (2025-12-31 → 2026-03-31): 0 new, 3 increased, 2 decreased, 0 exited. Change counts cover only managers that filed 13F reports in BOTH quarters, derived between two quarter-end snapshots — not same-day trades; a single manager is never said to have "bought" or "sold".
Institutional holdings are quarter-end long positions reported on SEC Form 13F-HR, filed up to 45 days after the quarter ends — they are delayed, are not real-time trades, exclude short positions and most non-US securities, and are not investment advice. Any increase/decrease is a reported change between two quarterly snapshots, not a same-day purchase or sale. These are quarter-end snapshots from the 13F filings on SEC EDGAR, filed within 45 days — not real-time, and any change is a difference between two quarterly reports, not a same-day trade. Informational only — not financial advice.
Short interest (FINRA)
CSTL had 1,561,988 shares of reported short interest as of the 2026-07-31 FINRA settlement date (delayed, bi-monthly; not real-time).
CSTL had 5.11% of its shares outstanding sold short as of the 2026-07-31 FINRA settlement date (percent of FLOAT would be higher — float is not disclosed in the source). FINRA reported 3.17 days to cover at the same settlement.
- Reported short interest (shares) 1,561,988
- Short interest (% of shares outstanding) 5.11%
- Prior settlement (shares) 1,421,793
- Reported change 9.86%
- Days to cover (reported) 3.17
Reported to FINRA as of the 2026-07-31 settlement date. Short interest is reported to FINRA and published on a delayed, bi-monthly schedule (as of a settlement date, disseminated roughly eight business days later) — it is NOT real-time, does not cover every venue or all US trading, and is not a short-squeeze prediction or investment advice. Days-to-cover is the value FINRA reports; percent of float is not shown because the source file carries no share-count denominator — where a percent appears it is of shares OUTSTANDING, the larger base, and is therefore a floor on percent of float. Informational only — not financial advice.
Competitors & peers
- Myriad Genetics (MYGN)
- Exact Sciences (EXAS)
- Natera (NTRA)
- Guardant Health (GH)
- NeoGenomics (NEO)
AI-enriched competitor set. Linked names are companies covered by stocks-llm; other named peers are shown for reference only.
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Frequently asked questions
What does CASTLE BIOSCIENCES INC (CSTL) do?
Castle Biosciences is a diagnostics company focused on providing prognostic and predictive tests for dermatologic and gastroenterologic cancers. The company utilizes proprietary gene expression profile (GEP) and other technologies to help clinicians make more informed treatment decisions. Its test portfolio assists in managing conditions such as cutaneous melanoma, squamous cell carcinoma, and Barrett’s esophagus.
What sector is CASTLE BIOSCIENCES INC (CSTL) in?
CASTLE BIOSCIENCES INC (CSTL) is classified in the Health Care sector. Its industry is Molecular Diagnostics. It trades on NASDAQ.
Who are CASTLE BIOSCIENCES INC's (CSTL) competitors?
Notable peers of CASTLE BIOSCIENCES INC (CSTL) include Myriad Genetics, Exact Sciences, Natera, Guardant Health and NeoGenomics. This peer set is informational only — not financial advice.
Is CASTLE BIOSCIENCES INC (CSTL) overbought or oversold right now?
CASTLE BIOSCIENCES INC (CSTL) is currently in overbought territory (its 14-day RSI is 71, above 70) (as of 2026-08-21). RSI describes recent price momentum, not a forecast — informational only, not financial advice.
Where does stocks-llm's data on CSTL come from?
Fundamentals and prices come from market data, as of 2026-08-24; company filings and profile facts come from SEC EDGAR. All figures are delayed daily-close data shown with their as-of date — informational only, not financial advice.
Fundamentals: market data, as of 2026-08-24. Filings: SEC EDGAR. Prices are delayed daily-close data.
Last updated 2026-08-21.
Informational only — NOT financial advice. All figures are delayed daily-close data from SEC EDGAR & market data, shown with their as-of date.