Every 8-K that Castle Biosciences, Inc. (CSTL) has filed with the SEC in the last 24 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A 8-K covers material events a company has to report between its quarterly reports, so if you follow CSTL and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full CSTL filings page.
Castle Biosciences reported strong top-line growth in Q2 2026. Revenue was $103.5 million, up from $86.2 million in Q2 2025, as total test reports for core diagnostics DecisionDx-Melanoma and TissueCypher rose 32%. GAAP gross margin was 74.9% and Adjusted Gross Margin was 76.3%. The company posted a small net loss of $2.1 million, or $0.07 per share, versus net income of $4.5 million a year earlier, while Adjusted EBITDA improved to $12.4 million from $10.4 million.
For the first six months of 2026, revenue reached $187.2 million, compared with $174.2 million in 2025. Cash, cash equivalents and marketable investment securities totaled $266.8 million as of June 30, 2026. Net cash used in operations was $6.9 million in the first half, versus $14.8 million provided a year earlier. Reflecting demand trends, Castle raised its 2026 total revenue guidance to $365–375 million from $345–355 million and now expects positive Adjusted EBITDA in the third quarter, fourth quarter and full year 2026.
Operationally, test volumes for TissueCypher and AdvanceAD-Tx grew, DecisionDx-SCC volumes softened, and new clinical and regulatory milestones were achieved, including New York State approval and an industry award for AdvanceAD-Tx and additional supportive studies for DecisionDx-Melanoma and TissueCypher.
Castle Biosciences, Inc. reported the results of its 2026 annual meeting of stockholders. Stockholders elected three Class I directors — Ellen Goldberg, Miles D. Harrison and Tiffany P. Olson — each to serve until the 2029 annual meeting, with support ranging from 14.4 million to 15.6 million votes in favor and 2.4 million broker non-votes. They also ratified the selection of KPMG LLP as independent registered public accounting firm for the fiscal year ending December 31, 2026, with 24.5 million votes for and minimal opposition. In advisory and related votes, stockholders approved the compensation of the company’s named executive officers, with about 21.3 million votes in favor versus 1.3 million against, and approved the non-employee director compensation policy by similar margins.
Castle Biosciences reported first-quarter 2026 results, with revenue of $83.7 million. Revenue declined from $88.0 million a year earlier, but core tests DecisionDx-Melanoma and TissueCypher grew volumes 16% and 58%, driving a 36% combined increase.
GAAP gross margin was 73%, with non-GAAP Adjusted Gross Margin of 75.6%. The company posted a net loss of $14.5 million and Adjusted EBITDA of $(5.1) million. Cash, cash equivalents and marketable securities totaled $261.7 million.
Castle raised its 2026 total revenue guidance to $345–355 million from $340–350 million, citing momentum in core tests and expanding clinical evidence across dermatology, gastroenterology and atopic dermatitis, including new data supporting DecisionDx-Melanoma, TissueCypher and AdvanceAD-Tx.
Castle Biosciences reported modest revenue growth for 2025 but a return to losses as reimbursement and amortization headwinds weighed on results. Full-year revenue was $344.2 million, up 4% from 2024, while total test reports for core dermatologic and GI drivers DecisionDx-Melanoma and TissueCypher grew 37%. TissueCypher volumes nearly doubled, rising to 39,014 tests from 20,956.
Despite strong volume, Medicare coverage changes for DecisionDx-SCC and discontinuation of IDgenetix limited top-line growth. Gross margin was 69% and Adjusted Gross Margin 80%, down from 79% and 82% in 2024, affected by lower DecisionDx-SCC revenue and a one-time $20.1 million amortization acceleration. Full-year net cash from operations was resilient at $64.3 million.
The company swung to a 2025 net loss of $24.2 million, versus net income of $18.2 million in 2024, with net loss per share of $0.83 and Adjusted Net Loss per Share of $0.14. Adjusted EBITDA declined to $44.0 million from $75.0 million. As of December 31, 2025, cash, cash equivalents and marketable securities totaled $299.5 million. Fourth-quarter revenue was $87.0 million, essentially flat year over year, with a quarterly net loss of $2.3 million. For 2026, Castle guides to total revenue of $340–350 million, implying roughly stable sales as it focuses on expanding adoption of its test portfolio, including the new AdvanceAD-Tx atopic dermatitis test.
Castle Biosciences, Inc. reported that it has shared an early look at its recent business performance. On January 11, 2026, the company issued a press release with certain preliminary performance results for the fourth quarter of 2025 and for the full year ended December 31, 2025, which is provided as Exhibit 99.1.
The company also released an investor slide presentation on the same date, attached as Exhibit 99.2, which management may use in future meetings. Both the preliminary results and the slide presentation are being furnished under Items 2.02 and 7.01, respectively, and are expressly stated as not being deemed “filed” for purposes of the Exchange Act or incorporated by reference into other filings unless specifically referenced.
Castle Biosciences (CSTL) furnished an update on its business by announcing financial results for the third quarter ended September 30, 2025, via a press release attached as Exhibit 99.1. The company also made available an investor slide presentation as Exhibit 99.2.
The materials were furnished under Items 2.02 and 7.01 and are not deemed “filed” for purposes of Section 18 of the Exchange Act, nor incorporated into other filings except by specific reference.
On August 5, 2025, Castle Biosciences, Inc. adopted amended and restated bylaws effective the same date. The A&R Bylaws revise stockholder nomination and advance-notice procedures by requiring nominees to be stockholders of record at the annual meeting, expanding disclosure and certification obligations for proponents and nominees, limiting the number of stockholder-submitted nominees to the number of directors up for election, and incorporating the Rule 14a-19 universal proxy requirements. The bylaws change meeting mechanics by setting quorum as a majority of voting power, making approval the majority of votes cast (excluding abstentions and broker non-votes), adjusting the annual-meeting alternative window (applies if advanced by more than 30 days or delayed by more than 70 days), and clarifying special meeting procedures. Other amendments update indemnification and expense-advancement provisions, refer to the certificate of incorporation for certain determinations, and require the full A&R Bylaws be filed as Exhibit 3.1.