Ultragenyx sinks as Phase 3 Angelman trial miss slams a key pipeline bet

Ultragenyx Pharmaceutical (RARE) is down 44.4% today. Here is some analysis on what might have caused this price movement.

Analysis: The selloff appears tied to Ultragenyx’s September 2, 2026 disclosure that its Phase 3 Aspire study of apazunersen in Angelman syndrome missed both its primary and key secondary endpoints. That result likely reset investor expectations for one of the company’s most important late-stage pipeline programs, and the pressure seems to have intensified as analysts cut ratings and price targets after the news.

Details:

Ultragenyx said apazunersen did not show a statistically significant benefit on cognition versus sham treatment in the pivotal Aspire study.

The company also said the trial missed a key secondary endpoint tied to broader clinical response, deepening concern that the program may have a more difficult path forward.

Management said it will evaluate planned operations and implement significant expense reductions, signaling that the setback could have meaningful strategic and financial consequences.

After the data release, several Wall Street firms lowered their views on the stock, which may have added to the sharp repricing.

Sources:

Ultragenyx Pharmaceutical, SEC, Yahoo Finance

Disclaimer: This price movement analysis was generated with the help of AI. Please double-check the information provided for mistakes.

$RARE Insider Trading Activity

$RARE insiders have traded $RARE stock on the open market 12 times in the past 6 months. Of those trades, 0 have been purchases and 12 have been sales.

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

HOWARD HORN (Chief Financial Officer) has made 0 purchases and 5 sales selling 23,413 shares for an estimated $598,080.
KARAH HERDMAN PARSCHAUER (EVP and Chief Legal Officer) has made 0 purchases and 4 sales selling 13,325 shares for an estimated $302,412.
SHEHNAAZ SULIMAN sold 5,740 shares for an estimated $144,188
CORAZON (CORSEE) D. SANDERS sold 2,000 shares for an estimated $50,100
ERIC CROMBEZ (EVP and Chief Medical Officer) sold 344 shares for an estimated $8,586

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 insider transaction endpoint.

$RARE Hedge Fund Activity

We have seen 174 institutional investors add shares of $RARE stock to their portfolio, and 179 decrease their positions in their most recent quarter.

Here are some of the largest recent moves:

RTW INVESTMENTS, LP added 4,148,100 shares (+113.7%) to their portfolio in Q2 2026, for an estimated $138,505,059
BLACKROCK, INC. added 3,354,678 shares (+46.0%) to their portfolio in Q2 2026, for an estimated $112,012,698
BAKER BROS. ADVISORS LP removed 2,772,692 shares (-100.0%) from their portfolio in Q1 2026, for an estimated $58,087,897
ASSENAGON ASSET MANAGEMENT S.A. added 2,057,951 shares (+1030.4%) to their portfolio in Q1 2026, for an estimated $43,114,073
SUVRETTA CAPITAL MANAGEMENT, LLC removed 2,019,000 shares (-100.0%) from their portfolio in Q1 2026, for an estimated $42,298,050
AQR CAPITAL MANAGEMENT LLC added 1,982,785 shares (+43.3%) to their portfolio in Q2 2026, for an estimated $66,205,191
JACOBS LEVY EQUITY MANAGEMENT, INC added 1,508,648 shares (+105.4%) to their portfolio in Q2 2026, for an estimated $50,373,756

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 13F endpoint.

$RARE Price Targets

Multiple analysts have issued price targets for $RARE recently. We have seen 9 analysts offer price targets for $RARE in the last 6 months, with a median target of $43.0.

Here are some recent targets:

Luca Issi from RBC Capital set a target price of $40.0 on 07/07/2026
Kristen Kluska from Cantor Fitzgerald set a target price of $96.0 on 05/21/2026
Laura Chico from Wedbush set a target price of $26.0 on 05/08/2026
Debjit Chattopadhyay from Guggenheim set a target price of $43.0 on 05/08/2026
Benjamin Burnett from Wells Fargo set a target price of $47.0 on 05/06/2026
Eliana Merle from Barclays set a target price of $43.0 on 04/29/2026
Jeffrey Hung from Morgan Stanley set a target price of $67.0 on 04/16/2026

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.