Mirum Pharma COO Buys Shares, Signals Confidence Amid Volatile Earnings and Options‑Heavy Insider Play

Insider Activity Spotlight: Mirum Pharmaceuticals’ COO Buys Shares While the Market Stays Quiet

On March 6, 2026, Mirum Pharmaceuticals’ President and Chief Operating Officer, Peter Radović, executed a modest purchase of 5,912 shares at $15.87 per share, raising his stake to 26,567 shares. The transaction, filed under Form 4, represents a 17 % increase in his holdings since the previous trade on January 21. Though the trade size is small relative to the company’s market cap (~$5.4 bn), it signals a continued confidence from the executive in Mirum’s long‑term prospects. The purchase occurs just after the stock closed at $90.93, a 1.4 % decline from the prior week, but the price has remained relatively stable after a sharp rally that lifted the share to a 52‑week high of $109.28 earlier in February.

What This Means for Investors

Radović’s buying, coupled with a recent sale of 5,912 stock options (now exercisable at a strike price well below market value), suggests a strategic shift in his personal exposure. By converting options into shares, the COO reduces the dilution risk that would arise if the options were exercised at a later date. For shareholders, such activity can be interpreted as a bullish endorsement: the executive is willing to lock in ownership at current levels rather than waiting for a future price spike. However, the trade’s modest size and the company’s volatile earnings environment—evidenced by a negative P/E of –190.1—mean that the signal should be weighed against broader market uncertainty. Investors might view the purchase as a positive cue, but should still monitor subsequent quarterly earnings and pipeline progress before committing significant capital.

Radović’s Insider‑Trading Pattern

Looking back over the past three months, Radović has alternated between buying and selling common stock, restricted stock units (RSUs), and performance‑restricted units. His most recent sale on January 26 of 3,143 shares at $96.19 preceded a buy on March 6, indicating a short‑term rebalancing of his portfolio. Historically, Radović’s transactions average a 5–10 % change in holdings per trade, with a tendency to buy RSUs and performance units early in the year and liquidate common shares later. This pattern reflects a classic “buy‑low, sell‑high” approach, aligning his interests with the company’s long‑term performance while maintaining liquidity for personal needs.

Company‑Wide Insider Activity Context

Mirum’s other insiders—Chief Executive Officer Christopher Peetz, SVP Global Controller Jolanda Howe, and Chief Medical Officer Joanne Quan—have also been active. Peetz’s recent sale of 9,108 shares at $103.30 and a subsequent purchase of 67,000 options suggests a similar conversion strategy. The overall insider activity, though frequent, is largely concentrated in options and RSUs, indicating executives are confident in the company’s growth trajectory but prefer the flexibility of options to manage tax and dilution impacts.

Bottom Line

Radović’s March 6 share purchase is a modest yet meaningful gesture that reaffirms executive confidence amid a volatile market. For investors, it underscores a potential upward bias, yet the negative earnings environment and the company’s heavy R&D spend warrant cautious optimism. The COO’s pattern of buying performance‑restricted units and selling common stock suggests a long‑term horizon, so stakeholders should monitor upcoming clinical milestones and financial disclosures to gauge whether Mirum’s trajectory justifies a sustained investment.