Investigation in Progress — No Complaint Filed Yet
BG&G is actively investigating potential securities fraud claims against Ultragenyx Pharmaceutical Inc.. If a complaint is filed, this page will be updated. Investors are encouraged to contact us now to preserve their rights.
Bronstein, Gewirtz & Grossman, LLC is investigating potential claims on behalf of purchasers of Ultragenyx Pharmaceutical Inc. (“Ultragenyx” or “the Company”) (NASDAQ: RARE). Investors who purchased Ultragenyx securities are encouraged to obtain additional information and assist the investigation.
The investigation concerns whether Ultragenyx has violated federal securities laws.
Ultragenyx Investigation Details
On September 2, 2026, Ultragenyx issued a press release “announc[ing] results from the Phase 3 Aspire study for apazunersen (GTX-102) in Angelman syndrome.” Per the press release, “[t]he study did not achieve the primary endpoint of change from Baseline in Bayley-4 cognitive raw score nor the key secondary endpoint of net response in Multidomain Responder Index (MDRI).” On this news, Ultragenyx’s stock price fell $11.68 per share, or 44.03%, to close at $14.85 per share on September 3, 2026.
What’s Next for Ultragenyx Investors?
If you are aware of any facts relating to this investigation or purchased Ultragenyx securities, you can assist this investigation. You can also contact Peretz Bronstein or his client relations manager, Nathan Miller, of Bronstein, Gewirtz & Grossman, LLC: 917-590-0911
RARE — Stock Performance
About Bronstein, Gewirtz & Grossman, LLC
We represent investors in class actions on a contingency fee basis. That means we will ask the court to reimburse us for out-of-pocket expenses and attorneys' fees, usually a percentage of the total recovery, only if we are successful.
Bronstein, Gewirtz & Grossman, LLC is a nationally recognized firm that represents investors in securities fraud class actions and shareholder derivative suits. Our firm has recovered hundreds of millions of dollars for investors nationwide.
“Our practice centers on restoring investor capital and ensuring corporate accountability, which serves to uphold the essential integrity of the marketplace.”