Castle Biosciences, Inc. (CSTL)

Castle Biosciences' stock has experienced significant movement, with a 100.1% price return in the past six months. As of January 6, 2026, the share price was $40.07, a 24.56% increase from January 7, 2025. Key events include strong Q1 2025 results, the Q3 2025 earnings report and AdvanceAD-Tx launch, preliminary Q4 and full-year 2025 results, and Medicare coverage changes that affected some test volumes.

The Healthcare sector generally experiences seasonal strength from April 25 to December 4. Analysis of seasonal charts over the past five years suggests a "Buy Date of June 5 and a Sell Date of September 21" has resulted in strong returns above the S&P 500 Total Return Index. However, only five years of data are available for this analysis. The company's CEO has indicated that the fourth quarter typically sees "flattish or down a bit to the third quarter in terms of normal seasonality."

Castle Biosciences, Inc. is a molecular diagnostics company focused on improving health outcomes through innovative tests. The company operates in the Healthcare sector, specifically in Diagnostics & Research and Medical Specialties. Its portfolio includes tests for dermatologic cancers, Barrett's esophagus, uveal melanoma, and mental health conditions. Key products include DecisionDx-Melanoma, DecisionDx-SCC, MyPath Melanoma, TissueCypher Barrett's Esophagus, DecisionDx-UM, DecisionDx-PRAME, DecisionDx-UMSeq, AdvanceAD-Tx, DecisionDx-CMSeq, and IDgenetix (discontinued in May 2025).

Castle Biosciences, Inc. is headquartered in Friendswood, Texas, and has laboratory facilities in Phoenix, Arizona, and Pittsburgh, Pennsylvania.

Castle Biosciences has a positive brand reputation, earning a Houston Chronicle Top Workplaces Award for the fifth consecutive year, indicating a strong internal culture and employee satisfaction. The company's reports also have an aggregate usefulness score of 4.8 out of 5.0 based on 55 reviews.

Castle Biosciences has a significant institutional ownership presence, with 381 institutional owners and shareholders holding a total of 32,451,365 shares, representing approximately 85.73% to 91.05% of the company's stock. Major institutional owners include BlackRock, Inc., Vanguard Group Inc, Principal Financial Group Inc, Portolan Capital Management, LLC, Dimensional Fund Advisors LP, Nuveen, LLC, Braidwell Lp and State Street Corp. Insider ownership is relatively low, ranging from 1.94% to 15.13%. Sofinnova Healthquest Partners LP is a large individual shareholder, owning 1.43 million shares, representing 4.91% of the company. Derek J. Maetzold, the CEO, also holds a significant number of shares.