Mirum Pharmaceuticals Falls 7.1% as Investors Appear to Reassess Near-Term Biotech Catalysts

Mirum Pharmaceuticals (MIRM) is down 7.1% today. Here is some analysis on what might have caused this price movement.

Analysis: A single fresh headline directly tied to today’s selloff is not obvious, so the move appears to be driven more by sentiment than by a clearly disclosed negative event. This could be because investors are taking profits and trimming risk ahead of a September 26, 2026 FDA decision date for zilurgisertib, while also weighing a recent chief medical officer transition and recent insider selling activity.

Details:

The company’s most recent business update highlighted a September 26, 2026 PDUFA target action date for zilurgisertib, creating a typical binary event that can increase biotech volatility as the decision approaches.

Mirum recently disclosed a leadership change in its medical organization, with Rob Myers appointed to succeed Joanne Quan as chief medical officer, and Dr. Quan’s separation scheduled to follow.

A recent SEC Form 4 showed the chief executive officer sold shares after exercising options in early September, which can sometimes pressure sentiment even when transactions are pre-planned or compensation-related.

Mirum has also been active on the investor conference circuit this month, which can sharpen focus on execution timelines and near-term regulatory expectations rather than providing a new upside catalyst.

Sources:

SEC, Mirum Pharmaceuticals, Nasdaq

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

$MIRM Insider Trading Activity

$MIRM insiders have traded $MIRM stock on the open market 32 times in the past 6 months. Of those trades, 0 have been purchases and 32 have been sales.

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

CHRISTOPHER PEETZ (CHIEF EXECUTIVE OFFICER) has made 0 purchases and 15 sales selling 100,000 shares for an estimated $10,259,288.
JOLANDA HOWE (SVP, GLOBAL CONTROLLER) has made 0 purchases and 5 sales selling 47,813 shares for an estimated $4,850,511.
ERIC BJERKHOLT (CHIEF FINANCIAL OFFICER) has made 0 purchases and 9 sales selling 25,944 shares for an estimated $2,657,952.
SAIRA RAMASASTRY has made 0 purchases and 3 sales selling 7,977 shares for an estimated $810,440.

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.

$MIRM Hedge Fund Activity

We have seen 186 institutional investors add shares of $MIRM stock to their portfolio, and 158 decrease their positions in their most recent quarter.

Here are some of the largest recent moves:

FMR LLC added 1,704,939 shares (+86.7%) to their portfolio in Q2 2026, for an estimated $199,597,208
INVESCO LTD. added 1,078,848 shares (+378.2%) to their portfolio in Q2 2026, for an estimated $126,300,735
WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC added 1,068,040 shares (+317.2%) to their portfolio in Q2 2026, for an estimated $125,035,442
PRICE T ROWE ASSOCIATES INC /MD/ added 938,186 shares (+54.6%) to their portfolio in Q2 2026, for an estimated $109,833,435
D. E. SHAW & CO., INC. removed 920,282 shares (-97.1%) from their portfolio in Q2 2026, for an estimated $107,737,413
PARADIGM BIOCAPITAL ADVISORS LP removed 625,000 shares (-100.0%) from their portfolio in Q2 2026, for an estimated $73,168,750
POLAR CAPITAL HOLDINGS PLC added 562,040 shares (+198.3%) to their portfolio in Q2 2026, for an estimated $65,798,022

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.

$MIRM Analyst Ratings

Wall Street analysts have issued reports on $MIRM in the last several months. We have seen 1 firms issue buy ratings on the stock, and 0 firms issue sell ratings.

Here are some recent analyst ratings:

TD Cowen issued a "Buy" rating on 05/07/2026

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

$MIRM Price Targets

Multiple analysts have issued price targets for $MIRM recently. We have seen 11 analysts offer price targets for $MIRM in the last 6 months, with a median target of $145.0.

Here are some recent targets:

Lisa Walter from RBC Capital set a target price of $148.0 on 07/07/2026
Jessica Fye from JP Morgan set a target price of $125.0 on 07/02/2026
Jonathan Wolleben from Citizens set a target price of $146.0 on 06/15/2026
Michael Ulz from Morgan Stanley set a target price of $150.0 on 06/11/2026
Yigal Nochomovitz from Citigroup set a target price of $145.0 on 06/02/2026
Kalpit Patel from Wolfe Research set a target price of $145.0 on 05/19/2026
Joseph Thome from TD Cowen set a target price of $145.0 on 05/07/2026

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.