$CSTL stock is down 23% today. Here's what we see in our data.

$CSTL stock has now fallen 23% today, according to our price data from Polygon. There has been approximately $31,111,840 of trading volume.

Here is what we see in our data on $CSTL (you can track the company live on Quiver's $CSTL stock page):

$CSTL Insider Trading Activity

$CSTL insiders have traded $CSTL stock on the open market 64 times in the past 6 months. Of those trades, 0 have been purchases and 64 have been sales.

Here’s a breakdown of recent trading of $CSTL stock by insiders over the last 6 months:

DEREK J MAETZOLD (Pres. & Chief Exec. Officer) has made 0 purchases and 50 sales selling 174,188 shares for an estimated $5,288,602.
KRISTEN M OELSCHLAGER (Chief Operating Officer) has made 0 purchases and 2 sales selling 33,820 shares for an estimated $1,249,805.
TOBIN W JUVENAL (Chief Commercial Officer) has made 0 purchases and 5 sales selling 39,456 shares for an estimated $1,213,070.
FRANK STOKES (Chief Financial Officer) has made 0 purchases and 5 sales selling 22,885 shares for an estimated $717,367.
G BRADLEY COLE has made 0 purchases and 2 sales selling 7,403 shares for an estimated $210,727.

To track insider transactions, check out Quiver Quantitative's insider trading dashboard. You can access data on insider stock transactions through the Quiver Quantitative API.

$CSTL Hedge Fund Activity

We have seen 97 institutional investors add shares of $CSTL stock to their portfolio, and 92 decrease their positions in their most recent quarter.

Here are some of the largest recent moves:

RTW INVESTMENTS, LP added 2,115,237 shares (+inf%) to their portfolio in Q4 2025, for an estimated $82,282,719
SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC added 658,725 shares (+164.7%) to their portfolio in Q4 2025, for an estimated $25,624,402
BRAIDWELL LP removed 645,552 shares (-78.5%) from their portfolio in Q4 2025, for an estimated $25,111,972
PARKMAN HEALTHCARE PARTNERS LLC removed 325,010 shares (-68.3%) from their portfolio in Q4 2025, for an estimated $12,642,889
EVENTIDE ASSET MANAGEMENT, LLC added 305,000 shares (+inf%) to their portfolio in Q4 2025, for an estimated $11,864,500
MILLENNIUM MANAGEMENT LLC removed 266,175 shares (-46.3%) from their portfolio in Q4 2025, for an estimated $10,354,207
SG AMERICAS SECURITIES, LLC added 223,624 shares (+1051.8%) to their portfolio in Q1 2026, for an estimated $5,489,969

To track hedge funds' stock portfolios, check out Quiver Quantitative's institutional holdings dashboard. You can access data on hedge funds moves and 13F filings through the Quiver Quantitative API.

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$CSTL Analyst Ratings

Wall Street analysts have issued reports on $CSTL in the last several months. We have seen 2 firms issue buy ratings on the stock, and 0 firms issue sell ratings.

Here are some recent analyst ratings:

Lake Street issued a "Buy" rating on 01/12/2026
Canaccord Genuity issued a "Buy" rating on 12/22/2025

To track analyst ratings and price targets for $CSTL, check out Quiver Quantitative's $CSTL forecast page.

$CSTL Price Targets

Multiple analysts have issued price targets for $CSTL recently. We have seen 5 analysts offer price targets for $CSTL in the last 6 months, with a median target of $47.0.

Here are some recent targets:

Catherine Ramsey from Baird set a target price of $43.0 on 05/07/2026
Kyle Mikson from Canaccord Genuity set a target price of $40.0 on 04/20/2026
Subbu Nambi from Guggenheim set a target price of $47.0 on 01/26/2026
Thomas Flaten from Lake Street set a target price of $52.0 on 01/12/2026
Mark Massaro from BTIG set a target price of $50.0 on 12/12/2025

You can track data on $CSTL on Quiver Quantitative.

This article is not financial advice. See Quiver Quantitative's disclaimers for more information. Note that there may be inaccuracies due to mistakes in ticker-mapping, and other anomalies.