Ultragenyx Faces Class Action Lawsuit Over Securities Violations
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Feb 19 2026
0mins
Should l Buy RARE?
Source: PRnewswire
- Class Action Initiation: Ultragenyx Pharmaceutical Inc. is facing a class action lawsuit for securities violations during the period from August 3, 2023, to December 26, 2025, with investors needing to apply as lead plaintiffs by April 6, 2026, indicating significant legal risks for the company.
- Stock Price Plunge: Following the announcements on July 9, 2025, and December 29, 2025, Ultragenyx's stock fell over 25% and 42%, respectively, due to the failure to achieve statistical significance in clinical trials, reflecting a severe loss of market confidence in its research capabilities.
- Details of Allegations: The lawsuit alleges that Ultragenyx misled investors by failing to disclose risks associated with its clinical trials, creating false expectations about its products, which could lead to substantial financial losses for investors.
- Law Firm Background: Robbins Geller Rudman & Dowd LLP, one of the world's leading class action firms, recovered over $916 million for investors in 2025, showcasing its strong capabilities and influence in securities fraud litigation.
Trade with 70% Backtested Accuracy
Stop guessing "Should I Buy RARE?" and start using high-conviction signals backed by rigorous historical data.
Sign up today to access powerful investing tools and make smarter, data-driven decisions.
Analyst Views on RARE
Wall Street analysts forecast RARE stock price to rise
18 Analyst Rating
17 Buy
1 Hold
0 Sell
Strong Buy
Current: 23.390
Low
35.00
Averages
61.65
High
120.00
Current: 23.390
Low
35.00
Averages
61.65
High
120.00
About RARE
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company. The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultrarare genetic diseases. Its therapies and clinical-stage pipeline consist of four product categories: biologics, small molecules, AAV gene therapy, and nucleic acid product candidates. Its four approved product candidates include Crysvita (burosumab) for the treatment of X-linked hypophosphatemia (XLH), and tumor-induced osteomalacia (TIO), Mepsevii (vestronidase alfa) for the treatment of mucopolysaccharidosis VII (MPSVII) or Sly Syndrome, Dojolvi (triheptanoin) for the treatment of long-chain fatty acid oxidation disorders (LC-FAOD), and Evkeeza (evinacumab) for the treatment of homozygous familial hypercholesterolemia (HoFH). Its clinical product candidates include DTX401, DTX301, UX701, UX143, UX111, and GTX-102. UX143 for the treatment of Osteogenesis Imperfecta.
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
Ultragenyx Pharmaceutical Faces Securities Fraud Class Action Lawsuit
- Lawsuit Background: Kessler Topaz Meltzer & Check, LLP has filed a securities fraud class action against Ultragenyx Pharmaceutical on behalf of investors who purchased shares between August 3, 2023, and December 26, 2025, indicating a significant erosion of investor trust in the company.
- Stock Price Plunge: On December 29, 2025, Ultragenyx shocked the market by revealing that its clinical trials failed to achieve statistical significance, causing its stock price to plummet 42% from $34.19 to $19.72, reflecting extreme disappointment in the company's prospects.
- False Statement Allegations: The lawsuit alleges that Ultragenyx misled investors regarding the efficacy of its drug for Osteogenesis Imperfecta, failing to disclose risks associated with its clinical trials, which exacerbated investor losses.
- Investor Action Recommendations: Affected investors are encouraged to seek lead plaintiff status by April 6, 2026, to represent the class in litigation, highlighting the importance of legal avenues in protecting investor rights.
See More
Class Action Filed Against Ultragenyx Pharmaceutical Inc.
- Lawsuit Background: Bronstein, Gewirtz & Grossman, LLC, a nationally recognized investor-rights law firm, has filed a class action lawsuit against Ultragenyx Pharmaceutical Inc. and certain officers, seeking damages for investors who purchased securities between August 3, 2023, and December 26, 2025, highlighting significant investor concerns regarding corporate transparency.
- Allegations of Misrepresentation: The complaint alleges that throughout the class period, the defendants made false and/or misleading statements and failed to disclose risks associated with the Phase III Orbit study on Osteogenesis Imperfecta, potentially leading investors to misjudge the company's prospects and the reliability of its data.
- Investor Action: Affected investors are encouraged to apply to be lead plaintiffs by April 6, 2026, to share in any recovery from the lawsuit, underscoring the importance of legal recourse in protecting investor rights and interests.
- Law Firm's Credentials: Bronstein, Gewirtz & Grossman, LLC has a strong reputation in securities fraud class actions, having recovered hundreds of millions for investors nationwide, emphasizing their commitment to restoring investor capital and ensuring market integrity.
See More
Faruqi & Faruqi Investigates Ultragenyx Securities Litigation
- Legal Investigation: Faruq & Faruqi, LLP is investigating potential securities fraud claims against Ultragenyx Pharmaceutical, urging investors who purchased shares between August 3, 2023, and December 26, 2025, to seek lead plaintiff status in a class action lawsuit by the April 6, 2026 deadline to protect their legal rights.
- Stock Price Plunge: Following Ultragenyx's announcement on July 9, 2025, that its Phase III Orbit study failed to achieve statistical significance, the stock price fell over 25%; further confirmation on December 29, 2025, that both the Orbit and Cosmic studies did not meet primary endpoints led to an additional drop of over 42%, reflecting severe market disappointment in the company's prospects.
- False Statement Allegations: The lawsuit alleges that Ultragenyx and its executives violated federal securities laws by making false and misleading statements regarding clinical trial results, failing to disclose associated risks, which severely undermined investor confidence in the company's future.
- Investor Rights Protection: Faruq & Faruqi encourages anyone with information regarding Ultragenyx's conduct, including whistleblowers and former employees, to come forward to better protect investor rights and advance the litigation process.
See More
Ultragenyx Faces Class Action Lawsuit Over Securities Violations
- Class Action Initiation: Robbins Geller law firm announces that purchasers of Ultragenyx Pharmaceutical stock between August 3, 2023, and December 26, 2025, can seek lead plaintiff status in a class action lawsuit, highlighting investor concerns over the company's financial transparency.
- Stock Price Plunge: On July 9, 2025, Ultragenyx revealed that its Phase III Orbit study failed to achieve statistical significance, causing the stock price to drop over 25%, indicating a severe lack of market confidence in the company's clinical trial results.
- Impact of Study Failures: On December 29, 2025, Ultragenyx announced that both its Orbit and Cosmic studies did not achieve statistical significance against primary endpoints, leading to a further 42% decline in stock price, suggesting significant challenges in R&D that could affect future financing capabilities.
- Legal Process Explanation: Under the Private Securities Litigation Reform Act of 1995, any investor who purchased Ultragenyx stock during the class period can seek lead plaintiff status, reflecting a decline in investor trust in the company's governance and management.
See More
Ultragenyx Pharmaceutical Class Action Notice Issued
- Class Action Notice: Rosen Law Firm reminds investors who purchased Ultragenyx (NASDAQ:RARE) common stock between August 3, 2023, and December 26, 2025, to apply as lead plaintiff by April 6, 2026, to potentially receive compensation without any out-of-pocket costs.
- Lawsuit Background: The lawsuit alleges that defendants misled investors regarding the efficacy of setrusumab (UX 143) in treating Osteogenesis Imperfecta, concealing adverse facts that led to inflated stock prices and subsequent investor losses when the truth emerged.
- Law Firm Credentials: Rosen Law Firm specializes in securities class actions, having recovered over $438 million for investors in 2019 alone, and was ranked No. 1 by ISS Securities Class Action Services in 2017, highlighting its expertise and resources in this legal domain.
- Investor Guidance: Investors are advised to carefully select legal counsel, as Rosen Law Firm emphasizes its track record in securities litigation, suggesting that investors choose firms with proven success to effectively protect their interests.
See More
Ultragenyx Pharmaceutical Class Action Reminder
- Litigation Timeline: Rosen Law Firm reminds investors who purchased Ultragenyx common stock between August 3, 2023, and December 26, 2025, that they must apply to be lead plaintiff by April 6, 2026, to participate in the class action and seek compensation.
- Lawsuit Background: The lawsuit alleges that defendants made false statements regarding the efficacy of setrusumab in Phase III Orbit and Cosmic studies, claiming it would significantly reduce annual fracture rates in Osteogenesis Imperfecta patients, while actual results did not support this claim, leading investors to buy shares at inflated prices.
- Law Firm Credentials: Rosen Law Firm specializes in securities class actions and recovered over $438 million for investors in 2019 alone, being ranked first by ISS Securities Class Action Services in 2017, showcasing its strong capabilities and successful track record in this field.
- Investor Guidance: Investors are advised to carefully select legal counsel, avoiding firms that lack actual litigation experience, to ensure effective legal support and potential compensation in the class action.
See More
Ultragenyx Pharmaceutical Faces Securities Fraud Class Action Lawsuit
- Lawsuit Background: Kessler Topaz Meltzer & Check, LLP has filed a securities fraud class action against Ultragenyx Pharmaceutical on behalf of investors who purchased shares between August 3, 2023, and December 26, 2025, indicating a significant erosion of investor trust in the company.
- Stock Price Plunge: On December 29, 2025, Ultragenyx shocked the market by revealing that its clinical trials failed to achieve statistical significance, causing its stock price to plummet 42% from $34.19 to $19.72, reflecting extreme disappointment in the company's prospects.
- False Statement Allegations: The lawsuit alleges that Ultragenyx misled investors regarding the efficacy of its drug for Osteogenesis Imperfecta, failing to disclose risks associated with its clinical trials, which exacerbated investor losses.
- Investor Action Recommendations: Affected investors are encouraged to seek lead plaintiff status by April 6, 2026, to represent the class in litigation, highlighting the importance of legal avenues in protecting investor rights.
See More
Class Action Filed Against Ultragenyx Pharmaceutical Inc.
- Lawsuit Background: Bronstein, Gewirtz & Grossman, LLC, a nationally recognized investor-rights law firm, has filed a class action lawsuit against Ultragenyx Pharmaceutical Inc. and certain officers, seeking damages for investors who purchased securities between August 3, 2023, and December 26, 2025, highlighting significant investor concerns regarding corporate transparency.
- Allegations of Misrepresentation: The complaint alleges that throughout the class period, the defendants made false and/or misleading statements and failed to disclose risks associated with the Phase III Orbit study on Osteogenesis Imperfecta, potentially leading investors to misjudge the company's prospects and the reliability of its data.
- Investor Action: Affected investors are encouraged to apply to be lead plaintiffs by April 6, 2026, to share in any recovery from the lawsuit, underscoring the importance of legal recourse in protecting investor rights and interests.
- Law Firm's Credentials: Bronstein, Gewirtz & Grossman, LLC has a strong reputation in securities fraud class actions, having recovered hundreds of millions for investors nationwide, emphasizing their commitment to restoring investor capital and ensuring market integrity.
See More
Faruqi & Faruqi Investigates Ultragenyx Securities Litigation
- Legal Investigation: Faruq & Faruqi, LLP is investigating potential securities fraud claims against Ultragenyx Pharmaceutical, urging investors who purchased shares between August 3, 2023, and December 26, 2025, to seek lead plaintiff status in a class action lawsuit by the April 6, 2026 deadline to protect their legal rights.
- Stock Price Plunge: Following Ultragenyx's announcement on July 9, 2025, that its Phase III Orbit study failed to achieve statistical significance, the stock price fell over 25%; further confirmation on December 29, 2025, that both the Orbit and Cosmic studies did not meet primary endpoints led to an additional drop of over 42%, reflecting severe market disappointment in the company's prospects.
- False Statement Allegations: The lawsuit alleges that Ultragenyx and its executives violated federal securities laws by making false and misleading statements regarding clinical trial results, failing to disclose associated risks, which severely undermined investor confidence in the company's future.
- Investor Rights Protection: Faruq & Faruqi encourages anyone with information regarding Ultragenyx's conduct, including whistleblowers and former employees, to come forward to better protect investor rights and advance the litigation process.
See More
Ultragenyx Faces Class Action Lawsuit Over Securities Violations
- Class Action Initiation: Robbins Geller law firm announces that purchasers of Ultragenyx Pharmaceutical stock between August 3, 2023, and December 26, 2025, can seek lead plaintiff status in a class action lawsuit, highlighting investor concerns over the company's financial transparency.
- Stock Price Plunge: On July 9, 2025, Ultragenyx revealed that its Phase III Orbit study failed to achieve statistical significance, causing the stock price to drop over 25%, indicating a severe lack of market confidence in the company's clinical trial results.
- Impact of Study Failures: On December 29, 2025, Ultragenyx announced that both its Orbit and Cosmic studies did not achieve statistical significance against primary endpoints, leading to a further 42% decline in stock price, suggesting significant challenges in R&D that could affect future financing capabilities.
- Legal Process Explanation: Under the Private Securities Litigation Reform Act of 1995, any investor who purchased Ultragenyx stock during the class period can seek lead plaintiff status, reflecting a decline in investor trust in the company's governance and management.
See More
Ultragenyx Pharmaceutical Class Action Notice Issued
- Class Action Notice: Rosen Law Firm reminds investors who purchased Ultragenyx (NASDAQ:RARE) common stock between August 3, 2023, and December 26, 2025, to apply as lead plaintiff by April 6, 2026, to potentially receive compensation without any out-of-pocket costs.
- Lawsuit Background: The lawsuit alleges that defendants misled investors regarding the efficacy of setrusumab (UX 143) in treating Osteogenesis Imperfecta, concealing adverse facts that led to inflated stock prices and subsequent investor losses when the truth emerged.
- Law Firm Credentials: Rosen Law Firm specializes in securities class actions, having recovered over $438 million for investors in 2019 alone, and was ranked No. 1 by ISS Securities Class Action Services in 2017, highlighting its expertise and resources in this legal domain.
- Investor Guidance: Investors are advised to carefully select legal counsel, as Rosen Law Firm emphasizes its track record in securities litigation, suggesting that investors choose firms with proven success to effectively protect their interests.
See More
Ultragenyx Pharmaceutical Class Action Reminder
- Litigation Timeline: Rosen Law Firm reminds investors who purchased Ultragenyx common stock between August 3, 2023, and December 26, 2025, that they must apply to be lead plaintiff by April 6, 2026, to participate in the class action and seek compensation.
- Lawsuit Background: The lawsuit alleges that defendants made false statements regarding the efficacy of setrusumab in Phase III Orbit and Cosmic studies, claiming it would significantly reduce annual fracture rates in Osteogenesis Imperfecta patients, while actual results did not support this claim, leading investors to buy shares at inflated prices.
- Law Firm Credentials: Rosen Law Firm specializes in securities class actions and recovered over $438 million for investors in 2019 alone, being ranked first by ISS Securities Class Action Services in 2017, showcasing its strong capabilities and successful track record in this field.
- Investor Guidance: Investors are advised to carefully select legal counsel, avoiding firms that lack actual litigation experience, to ensure effective legal support and potential compensation in the class action.
See More
