Form 4: Mirum CMO Sells Shares for Tax Obligations

Mirum Pharmaceuticals' Chief Medical Officer, Joanne Quan, reported the sale of common stock to cover tax obligations following the vesting of restricted stock units.

Summary

• Joanne Quan, Chief Medical Officer of Mirum Pharmaceuticals, Inc. (MIRM), reported transactions involving the company's common stock.
• On January 16, 2026, 12,500 restricted stock units (RSUs) vested, converting into 12,500 shares of common stock.
• These RSUs are part of a grant where 1/3rd vests on each anniversary of January 16, 2024, meaning this was the second annual vesting tranche.
• Following the RSU vesting, Ms. Quan's beneficial ownership of common stock increased to 18,216 shares, which also included 67 shares acquired via the Employee Stock Purchase Plan on November 10, 2025.
• On January 20, 2026, Ms. Quan sold 6,911 shares of common stock at a price of $90.2696 per share.
• The sale was conducted to cover tax withholding obligations associated with the vesting of the restricted stock units.
• After the sale, Ms. Quan's direct beneficial ownership of common stock stands at 11,305 shares.
• An additional 12,500 restricted stock units remain unvested, representing the final tranche of the original grant.

Sentiment

Score: 5

Explanation: The filing reports a routine insider transaction related to executive compensation and tax obligations, which is neutral in its implications for the company's operational or financial performance.

Positives

• The vesting of 12,500 restricted stock units indicates continued long-term incentive alignment between the Chief Medical Officer and shareholder interests.
• The acquisition of 67 shares through the Employee Stock Purchase Plan demonstrates ongoing participation in company equity programs.

Negatives

• The sale of 6,911 shares reduces the Chief Medical Officer's direct equity stake in the company, although it was for tax purposes.

Future Outlook

The filing indicates that 12,500 restricted stock units remain unvested, which are expected to vest on the three-year anniversary of the Vesting Commencement Date (January 16, 2027), assuming the 1/3rd annual vesting schedule continues.

Industry Context

This is a routine insider transaction filing common across all publicly traded companies, reflecting executive compensation practices involving equity awards and subsequent tax-related sales. It does not provide specific insights into broader industry trends or competitive positioning.

Comparison to Industry Standards

• The practice of executives selling shares to cover tax obligations upon RSU vesting is a standard and common occurrence in executive compensation across various industries, including pharmaceuticals.
• The use of Restricted Stock Units (RSUs) as a component of executive compensation is a widely adopted practice, aligning executive incentives with long-term shareholder value creation.

Stakeholder Impact

• Shareholders: The transaction is a routine insider sale for tax purposes and is unlikely to have a significant impact on shareholder sentiment or the company's valuation.
• Employees: The vesting of RSUs and participation in an ESPP reflect standard employee equity compensation practices.

Next Steps

• The remaining 12,500 restricted stock units are expected to vest on January 16, 2027, representing the final tranche of the original grant.

Key Dates

Recommendation

This Form 4 filing details a routine insider transaction where the Chief Medical Officer sold shares to cover tax obligations arising from RSU vesting. Such transactions are common and do not typically reflect a change in the company's fundamentals or management's outlook. Therefore, it provides no new information that would warrant a change in investment recommendation; a 'hold' stance is maintained based on existing company analysis.

Keywords

MIRM, Mirum Pharmaceuticals, Form 4, Insider Transaction, Restricted Stock Units, RSU Vesting, Stock Sale, Executive Compensation, Tax Withholding