Castle Biosciences, Inc. filings document the regulatory record for a Delaware molecular diagnostics company with common stock listed on the Nasdaq Global Market under CSTL. Recent Form 8-K filings report quarterly and annual operating results, preliminary performance updates, and Regulation FD slide presentations tied to management communications.
The company’s proxy materials cover annual meeting matters, executive compensation, director elections, stockholder voting procedures, and governance disclosures. Other material-event filings document amendments to bylaws, including provisions related to stockholder meetings, director nominations, and board governance, alongside standing disclosures on registered securities and exchange listing status.
An affiliate of CSTL has filed to sell common stock through a broker-dealer. The notice covers the potential sale of 22,500 shares of common stock, with an indicated aggregate market value of $630,000, to be sold through NASD on or after July 31, 2026.
The shares derive from multiple equity compensation grants, including Restricted Stock Units and Restricted Stock Awards acquired on dates such as December 10, 2021, February 28, 2022, August 9, 2024, December 9, 2024, and December 10, 2024, with individual grant sizes ranging from 494 to 12,074 shares.
Derek Maetzold and related trusts have filed a notice of intent to sell common stock of CSTL under Rule 144. The planned sales include 40,046 shares acquired on 05/10/2018 as compensation via stock options, to be disposed of through a compensation-related cashless exercise and same-day sale by 07/31/2026.
The disclosure also lists multiple sales of CSTL common stock during May–July 2026 by Maetzold and various family trusts, with individual transactions such as 6,214 shares for $137,290.52 on 05/07/2026 and 6,214 shares for $150,535.39 on 07/01/2026.
Castle Biosciences reported net revenues of $103.5 million for the three months ended June 30, 2026, up from $86.2 million a year earlier, driven by growth in non-dermatologic tests. Operating loss narrowed to $3.1 million and net loss was $2.1 million versus net income of $4.5 million in 2025.
For the first half of 2026, net revenues were $187.2 million compared with $174.2 million, while net loss improved to $16.6 million from $21.3 million. Total test reports rose to 57,755 from 50,976, led by TissueCypher (26,733 vs. 16,602) and DecisionDx‑Melanoma (20,301 vs. 18,602).
Cash and cash equivalents were $62.1 million and marketable investment securities $204.7 million at June 30, 2026; management expects these resources and anticipated revenues to cover at least the next 12 months. The company continues a limited launch of its AdvanceAD‑Tx test and is responding to an HHS OIG subpoena requesting historical billing information.
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 CEO Derek J. Maetzold exercised stock options for 6,214 shares of common stock at $2.39 per share and reported related sales totaling 9,836 common shares on July 27, 2026. Sales from direct holdings and several family trusts occurred at weighted-average prices of $24.13 and $25.06 per share, pursuant to a Rule 10b5-1 trading plan adopted on December 3, 2025. Following the option exercise, Maetzold held 78,903 options, and indirect holdings included 18,718, 44,323 and 40,935 common shares in three Grantor Retained Annuity Trusts.
Castle Biosciences Inc. President and Chief Executive Officer Derek J. Maetzold reported open-market sales of 4,172 shares of common stock on July 14, 2026 at a weighted-average price of about $22.92 per share, executed largely through family trusts and related entities.
He also exercised stock options for 550 shares at an exercise price of $2.39 per share. The sales were carried out under a Rule 10b5-1 trading plan adopted on December 3, 2025, and many positions are reported as indirect holdings through various Maetzold family trusts and grantor retained annuity trusts.
Castle Biosciences CEO Derek Maetzold reported option exercises and share sales in Castle Biosciences Inc. common stock. On July 1, 2026, he exercised options for 6,214 shares at $2.39 per share and related entities sold a combined 9,836 shares in open-market transactions at a weighted-average price of $24.29, pursuant to a pre-arranged Rule 10b5-1 plan.
Following these transactions, one direct holding shows 21,479 shares of common stock, and various family and grantor retained annuity trusts associated with Maetzold continue to hold additional indirect positions.
Castle Biosciences Chief Operating Officer Kristen M. Oelschlager reported open-market sales of a total of 8,586 shares of Common Stock on July 1, 2026, executed under a pre-arranged Rule 10b5-1 trading plan adopted on March 17, 2026.
The sales were completed in two weighted-average price transactions: 8,186 shares at $24.40 per share and 400 shares at $24.78 per share, across multiple trades within disclosed price ranges. Following these transactions, she holds 21,874 shares directly and 97,251 shares indirectly through the Fritz Shorter Trust, where she and her spouse serve as trustees and beneficiaries.
Multiple Rule 144 sale notices report transactions by Derek Maetzold and related trusts. The filings list numerous small open-market dispositions of Common shares carried out across April–June 2026 by trusts and entities associated with Maetzold. Examples include sales of 6,214 shares for $155,156.64 and 1,357 shares for $29,981.21 on the dates shown in the excerpt. The entries identify trusts (e.g., The Maetzold 2018 Remainder Trust, The Maetzold Descendants 2020 Trust) and an irrevocable trust as selling holders. Payment amounts are shown per sale line; the filing reports repeated, modest transactions over multiple dates.
CASTLE BIOSCIENCES INC Chief Operating Officer Kristen M. Oelschlager reported an open-market sale of 8,587 shares of common stock at a weighted-average price of $20.71 per share on June 16, 2026. The sale was executed as a planned transaction under a Rule 10b5-1 trading plan adopted on March 17, 2026.
Following this sale, she holds 30,460 shares of common stock directly and 97,251 shares indirectly through The Fritz Shorter Trust, where she and her spouse serve as trustees and beneficiaries.