Ultragenyx Pharmaceutical Securities Lawsuit Notification
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Mar 04 2026
0mins
Should l Buy RARE?
Source: Globenewswire
- Lawsuit Background: Kahn Swick & Foti LLC informs investors in Ultragenyx Pharmaceutical of a class action lawsuit due to alleged securities fraud occurring between August 3, 2023, and December 26, 2025, aimed at recovering losses for affected investors.
- Study Failure Impact: On December 26, 2025, Ultragenyx announced that its Phase 3 studies for setrusumab (UX143) failed to show a statistically significant reduction in annualized fracture rates for osteogenesis imperfecta patients, prompting the company to evaluate significant expense reductions.
- Stock Price Plunge: Following the announcement, Ultragenyx's stock price fell approximately 42%, from $34.19 per share on December 26, 2025, to $19.72 per share on December 29, 2025, indicating a negative market outlook on the company's future.
- Investor Action Recommendation: Affected investors have until April 6, 2026, to request to be appointed as lead plaintiff, although they can still share in any recovery without serving in that role, highlighting ongoing opportunities for legal recourse for investors seeking compensation.
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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: 21.820
Low
35.00
Averages
61.65
High
120.00
Current: 21.820
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.
- Lawsuit Background: Kahn Swick & Foti LLC has notified investors in Ultragenyx Pharmaceutical of a class action lawsuit due to alleged securities fraud occurring between August 3, 2023, and December 26, 2025, aiming to recover losses for affected investors.
- Stock Price Plunge: Following the announcement on December 26, 2025, that setrusumab (UX143) failed to show a statistically significant reduction in fracture rates in Phase III studies, Ultragenyx's stock price plummeted approximately 42%, from $34.19 to $19.72, indicating a negative market outlook on the company's future.
- Legal Action Deadline: Investors who suffered losses during the relevant period have until April 6, 2026, to request to be appointed as lead plaintiff, although participation in any recovery does not require serving as lead plaintiff, providing a pathway for legal recourse.
- Law Firm Background: Kahn Swick & Foti is recognized as one of the premier securities litigation law firms in the U.S., ranked among the top ten nationally based on total settlement value, focusing on supporting investors who have suffered losses due to corporate fraud.
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- Lawsuit Timeline: Ultragenyx Pharmaceutical Inc. faces a class action lawsuit for alleged violations of the Securities Exchange Act of 1934, with investors needing to apply as lead plaintiffs by April 6, 2026, indicating heightened legal risks for the company.
- Stock Price Volatility: Following the failure to achieve statistical significance in clinical trials, Ultragenyx's stock plummeted over 25% on July 9, 2025, and over 42% on December 29, 2025, reflecting market pessimism regarding the company's future prospects.
- Research Setbacks: The failure of Ultragenyx's Phase III Orbit and Cosmic studies to meet primary endpoint statistical significance highlights significant setbacks in drug development, potentially undermining market confidence and investor trust.
- Legal Representation Information: Robbins Geller law firm is encouraging affected investors to join the lawsuit, illustrating the dual pressure of legal and financial challenges on the company, which may impact its future fundraising capabilities.
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- Lawsuit Overview: Holzer & Holzer, LLC reminds investors of the class action lawsuit against BlackRock TCP Capital Corp., alleging that from November 6, 2024, to January 23, 2026, the company failed to appropriately value investments, resulting in significant investor losses.
- Mereo BioPharma Lawsuit: The class action against Mereo BioPharma Group plc claims that between June 5, 2023, and December 26, 2025, the company did not disclose material facts regarding setrusumab's statistical significance in the ORBIT and COSMIC studies, impacting investor confidence.
- Pomdoctor Lawsuit: The class action against Pomdoctor Limited alleges involvement in a fraudulent stock promotion scheme through social media misinformation from October 9, 2025, to December 11, 2025, leading to investor losses, with a deadline of April 6, 2026, to apply as lead plaintiff.
- Ultragenyx Lawsuit: The class action against Ultragenyx Pharmaceutical Inc. alleges failure to disclose expected results for its Phase III studies from August 3, 2023, to December 26, 2025, urging investors to act before the April 6, 2026, deadline.
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- Shareholder Notice Issued: The Gross Law Firm has issued a notice to shareholders of Ultragenyx Pharmaceutical Inc., encouraging those who purchased RARE shares between August 3, 2023, and December 26, 2025, to contact the firm regarding potential lead plaintiff appointment, which is not required for recovery participation.
- Allegations of Misleading Statements: The complaint alleges that Ultragenyx provided overly positive statements while concealing significant adverse facts about setrusumab's risks, misleading investors about the drug's potential effectiveness in clinical trials.
- Impact of Study Failures: On December 29, 2025, Ultragenyx announced that its Phase III Orbit and Cosmic studies failed to achieve statistical significance, causing the stock price to plummet by approximately 42.32% in one day, from $34.19 to $19.72, severely undermining investor confidence.
- Next Steps for Shareholders: Shareholders must register by April 6, 2026, to participate in the class action lawsuit, and upon registration, they will receive updates on the case's progress, ensuring their rights are protected.
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- Investigation Launched: Faruq & Faruqi, LLP is investigating potential claims against Ultragenyx Pharmaceutical Inc, focusing on investors who purchased securities between August 3, 2023, and December 26, 2025, highlighting concerns for investor rights.
- Legal Rights Reminder: The firm reminds investors that April 6, 2026, is the deadline to seek the role of lead plaintiff in a federal securities class action, emphasizing the importance of timely action to protect legal rights.
- Direct Contact Channels: Investors can directly contact Faruq & Faruqi partner Josh Wilson at 877-247-4292 or 212-983-9330 (Ext. 1310) for further legal advice and support regarding their claims.
- Market Impact Anticipation: This investigation may negatively impact Ultragenyx's stock price, prompting investors to monitor developments closely to assess risks and potential losses associated with their investments.
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- Class Action Notice: The Portnoy Law Firm has advised Ultragenyx Pharmaceutical investors of a class action for those who purchased securities between August 3, 2023, and December 26, 2025, with a deadline for lead plaintiff motions set for April 6, 2026.
- False Statement Allegations: The lawsuit alleges that Ultragenyx misled investors by creating a false impression regarding the efficacy of its drug setrusumab, particularly downplaying the risk that patients in the Phase III Orbit study might not achieve a statistically significant reduction in annualized fracture rate.
- Clinical Trial Risks: Ultragenyx is accused of failing to adequately communicate the risks associated with its Phase III Orbit study results, especially since the Phase II results lacked a placebo control group, potentially misleading investors about the drug's effectiveness and impacting their investment decisions.
- Legal Consultation Opportunity: The Portnoy Law Firm offers complimentary case evaluations and encourages investors to reach out to discuss their legal rights, demonstrating a commitment to supporting investor interests and recovery of losses.
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