Renaissance Technologies LLC Has $13.08 Million Stock Holdings in Castle Biosciences, Inc. $CSTL

Posted by Francis Steltz on Aug 1st, 2026

Renaissance Technologies LLC lifted its holdings in Castle Biosciences, Inc. (NASDAQ:CSTL – Free Report) by 8.1% in the first quarter, according to its most recent disclosure with the Securities & Exchange Commission. The fund owned 532,800 shares of the company’s stock after buying an additional 39,700 shares during the quarter. Renaissance Technologies LLC owned about 1.76% of Castle Biosciences worth $13,080,000 at the end of the most recent quarter.

Several other institutional investors and hedge funds have also added to or reduced their stakes in the stock. RTW Investments LP bought a new stake in Castle Biosciences during the 4th quarter worth about $82,283,000. Summit Partners Public Asset Management LLC raised its stake in shares of Castle Biosciences by 164.7% in the fourth quarter. Summit Partners Public Asset Management LLC now owns 1,058,725 shares of the company’s stock worth $41,184,000 after acquiring an additional 658,725 shares during the last quarter. Eventide Asset Management LLC bought a new position in shares of Castle Biosciences in the fourth quarter worth about $11,864,000. SG Americas Securities LLC lifted its position in shares of Castle Biosciences by 1,051.8% during the first quarter. SG Americas Securities LLC now owns 244,886 shares of the company’s stock worth $6,012,000 after purchasing an additional 223,624 shares in the last quarter. Finally, Wellington Management Group LLP acquired a new position in shares of Castle Biosciences during the fourth quarter worth approximately $8,502,000. Institutional investors and hedge funds own 92.60% of the company’s stock.

Trending Headlines about Castle Biosciences

Here are the key news stories impacting Castle Biosciences this week:

Positive Sentiment: Revenue significantly exceeded expectations: Second-quarter revenue was approximately $103.5 million, up 20.1% year over year and above analyst estimates near $86 million-$88 million. Gross profit increased 16.5% to $79.8 million. Castle Biosciences Reports Second Quarter 2026 Results
Positive Sentiment: Loss was narrower than expected: Adjusted loss was $0.07 per share, compared with the consensus estimate of a $0.41-$0.44 loss. The operating loss narrowed to $3.1 million, supporting the view that improving scale may help profitability over time. Castle Biosciences Reports Q2 Loss, Tops Revenue Estimates
Positive Sentiment: Full-year outlook was raised: Castle now expects 2026 revenue of $365 million to $375 million, above the approximately $353.2 million analyst consensus. The higher outlook strengthens the growth narrative and likely provided the main catalyst for the stock’s advance. Castle Biosciences Lifts 2026 Outlook After Q2 Growth
Neutral Sentiment: Liquidity remains solid: The company generated $15.2 million in operating cash flow and ended the quarter with $62.1 million in cash, while maintaining relatively low leverage. However, capital spending was $8.7 million and net profitability has not yet been achieved. Castle Biosciences Q2 2026 Earnings Call Transcript
Negative Sentiment: Insider selling remains a risk signal: Chief Executive Officer Derek Maetzold and other executives have reported stock sales, with the transactions conducted under pre-arranged Rule 10b5-1 plans. While these sales do not necessarily indicate deteriorating business conditions, the absence of reported insider purchases may temper investor enthusiasm.

Analyst Ratings Changes

CSTL has been the subject of a number of research reports. Weiss Ratings lowered shares of Castle Biosciences from a “sell (d-)” rating to a “sell (e+)” rating in a report on Monday, June 1st. Roth Capital started coverage on Castle Biosciences in a report on Wednesday, June 24th. They set a “buy” rating and a $40.00 price objective on the stock. Canaccord Genuity Group reduced their price objective on Castle Biosciences from $50.00 to $40.00 and set a “buy” rating on the stock in a report on Monday, April 20th. BTIG Research decreased their price objective on Castle Biosciences from $50.00 to $40.00 and set a “buy” rating on the stock in a research report on Wednesday, May 13th. Finally, Zacks Research cut Castle Biosciences from a “strong-buy” rating to a “hold” rating in a research note on Tuesday, May 26th. One investment analyst has rated the stock with a Strong Buy rating, seven have issued a Buy rating, one has given a Hold rating and one has issued a Sell rating to the company. According to MarketBeat, the company has an average rating of “Moderate Buy” and a consensus target price of $41.43.

Get Our Latest Stock Analysis on CSTL

Castle Biosciences Stock Up 4.5%

Shares of NASDAQ CSTL opened at $28.00 on Friday. Castle Biosciences, Inc. has a 1 year low of $14.59 and a 1 year high of $44.28. The firm’s 50-day moving average is $22.76 and its 200-day moving average is $26.52. The company has a current ratio of 6.75, a quick ratio of 6.53 and a debt-to-equity ratio of 0.02. The firm has a market capitalization of $849.24 million, a PE ratio of -42.42 and a beta of 1.00.

Castle Biosciences (NASDAQ:CSTL – Get Free Report) last posted its quarterly earnings results on Thursday, July 30th. The company reported ($0.07) earnings per share for the quarter, topping analysts’ consensus estimates of ($0.41) by $0.34. Castle Biosciences had a negative net margin of 5.43% and a negative return on equity of 4.16%. The business had revenue of $99.86 million during the quarter, compared to the consensus estimate of $86.23 million. Equities analysts expect that Castle Biosciences, Inc. will post -1.56 EPS for the current year.

Insiders Place Their Bets

In other news, insider Derek J. Maetzold sold 3,622 shares of the stock in a transaction on Monday, July 27th. The stock was sold at an average price of $24.16, for a total value of $87,507.52. Following the transaction, the insider owned 11,812 shares of the company’s stock, valued at $285,377.92. This represents a 23.47% decrease in their position. The transaction was disclosed in a document filed with the SEC, which is available through this hyperlink. The transaction was executed under a pre-arranged Rule 10b5-1 trading plan. Also, COO Kristen M. Oelschlager sold 8,586 shares of the firm’s stock in a transaction on Wednesday, July 1st. The stock was sold at an average price of $24.42, for a total value of $209,670.12. Following the completion of the transaction, the chief operating officer owned 21,874 shares in the company, valued at $534,163.08. This represents a 28.19% decrease in their ownership of the stock. Additional details regarding this sale are available in the official SEC disclosure. The transaction was executed under a pre-arranged Rule 10b5-1 trading plan. Insiders have sold a total of 55,025 shares of company stock valued at $1,252,199 in the last ninety days. Company insiders own 6.10% of the company’s stock.

Castle Biosciences Company Profile

(Free Report)

Castle Biosciences, Inc is a molecular diagnostics company specializing in the development and commercialization of prognostic and diagnostic tests for patients with dermatologic conditions. The company’s proprietary portfolio of genomic assays is designed to improve risk assessment and guide clinical decision-making for individuals with skin cancers and other skin-related diseases. By combining genomic data with advanced statistical algorithms, Castle Biosciences seeks to provide actionable insights that help physicians tailor treatment plans and monitoring strategies.

The company’s flagship test, DecisionDx-Melanoma, evaluates the probability of metastasis in patients diagnosed with cutaneous melanoma, supporting more personalized surveillance and therapeutic approaches.