Castle Biosciences Inc. (CSTL)

About Castle Biosciences Inc.

Castle Biosciences is a molecular diagnostics company that develops and offers tests to aid clinicians in diagnosing and treating dermatologic cancers, Barrett’s esophagus, atopic dermatitis, and uveal melanoma. Its main products include gene expression profile tests such as DecisionDx-Melanoma, TissueCypher, and AdvanceAD-Tx, which provide personalized information to guide treatment and patient management decisions. The company serves healthcare providers and patients by delivering clinically validated tests supported by peer-reviewed studies.

Snapshot

Fundamentals are from SEC filings for FY2025, the latest annual period (ended December 31, 2025). P/E and market cap are derived from stored market prices, last retrieved on a rolling basis and typically within the past week.

Peer comparison

Where Castle Biosciences’s fundamentals sit among the 570 Healthcare companies. Each figure is ranked only against peers that report it, from lowest (left) to highest (right).

Castle Biosciences’s long-term debt to equity of 0.02 ranks in the 10th percentile of the 251 Healthcare companies reporting it. Castle Biosciences’s gross margin of 79.4% ranks in the 89th percentile of the 290 Healthcare companies reporting it.

No reported insider purchases (code P) in the last 90 days; 85 insider sales totaling $8.3M. For context, about 15% of companies in the universe saw any reported insider purchase (code P) in the same window. Browse insider activity →

Percentiles describe where a figure sits among sector peers reporting it (100th = highest). They are position within a peer group, not a rating, and not investment advice. Short interest ranking uses days to cover from FINRA Consolidated Short Interest data; FINRA is the owner and source of that data, included at no additional charge.

Institutional ownership

Held by 7 quant / multi-strat books among the superinvestors we track; no conviction manager currently reports a position.

From quarterly Form 13F filings, which can be up to 45 days delayed. Long US-listed positions only: excludes short positions, options, cash, bonds, and non-US holdings, so this is not a manager’s complete portfolio. Counts are of the investors we track, not all institutions. Not investment advice.

Recent insider activity

Non-derivative buys and sells (codes P/S) reported by officers, directors and 10% owners on SEC Form 4.

Reported non-derivative purchases and sales (codes P/S), which may be open-market or private. Excludes option exercises, grants, and shares withheld for taxes. Dates shown are the trade date; a Form 4 can be filed days to years later. A sale can be routine (e.g. a pre-set 10b5-1 plan), so read individual transactions in context. From SEC Form 4. Not investment advice.

Short interest

Total shares sold short as of each twice-monthly FINRA settlement. Rising short interest means more investors are positioned against the stock; days to cover estimates how many trading days of average volume that position represents.

Source: FINRA Consolidated Short Interest. FINRA is the owner and source of the FINRA-supplied data, which is included at no additional charge for your own personal or professional use; republishing or redistributing it is not permitted. Settlement dates are shown; FINRA publishes each settlement about nine business days later, so the latest figure can be two to four weeks old. Not presented as a percentage of float. No FINRA endorsement of this product is implied. Not investment advice.

Quarterly trend

Latest 8 quarters, from company XBRL filings on SEC EDGAR. A dotted underline marks a fourth-quarter figure we calculated from the full year and the first nine months. Revenue YoY is our calculation too: each quarter against the same quarter a year earlier.

Company facts

Selected SEC filings

Largest Healthcare peers

All Healthcare companies →