Analyst upgrades pile up as MIRM shorts sit tight ahead of November earnings

Mirum Pharmaceuticals closed Tuesday at $85.07, up 6.8% on the week, yet eight analysts have raised their price targets over the past two weeks without a single downgrade, leaving the stock trading at roughly a 45% discount to the Street's mean target of $153.

The analyst wave is the defining feature of the week. Morgan Stanley raised its target to $152 from $137 on October 13, maintaining Overweight. TD Cowen followed this week, lifting to $145 from $140 with a Buy. In between, Stifel moved to $156, Evercore ISI to $146, Citigroup to $184, and RBC Capital to $155, all raises, none with a rating change. Every action in the past month has been a target increase. The consensus is not divided on direction; the debate is about magnitude and timing, with Citigroup at $184 and HC Wainwright at $200 sitting well above the group. The bull case centres on brelovitug's Phase 3 AZURE-1 data in hepatitis delta virus, both doses clearing the composite endpoint at Week 24 with clean safety, plus the September 25 FOP approval of Atebrioz. Management has pointed to more than $750 million in peak HDV revenue potential. The bear case focuses on unresolved programs in biliary atresia, primary sclerosing cholangitis, and primary biliary cholangitis, each still needing positive readouts, plus ongoing net losses and the possibility of further dilution before the company reaches cash-flow breakeven.

Short interest tells a quieter story than the analyst activity would suggest. At 13.2% of the free float, roughly 6.8 million shares are borrowed, and that figure has been essentially flat all week, up less than 0.4% over seven days after rising about 9.4% over the past month. The borrow market is nowhere near stressed. Availability is at 505%, meaning there are five shares in the lending pool for every one already borrowed, well above the 52-week low of 276%. Cost to borrow is 0.56%, up modestly on the month but still low in absolute terms. With days-to-cover at 7.67 per the most recent FINRA fortnightly report, short sellers are not trapped, but they have not moved to cut either. The position has drifted higher over October without any urgency in either direction.

Options positioning is similarly measured. The put/call ratio is 0.55, just below its 20-day average of 0.56, with a z-score near zero. That is far from the 52-week high of 1.34, and the recent drift lower in the ratio suggests call activity has ticked up relative to puts as the stock recovered from its one-month low. This is not a market pricing in a squeeze or a crash; it reads as broadly neutral ahead of the November 2 earnings date.

Insider activity over the past 90 days has produced a net sale of approximately 108,000 shares, worth around $10.8 million. The more notable transactions are the September 1 CEO sales, which together totalled around $3 million under pre-arranged 10b5-1 plans. CFO Eric Bjerkholt sold nearly 10,000 shares at $98.37 on September 14 outside any disclosed plan, a figure worth flagging, though the stock has since pulled back to $85. The option exercises and awards in the same window are compensation mechanics and carry less signal. On the institutional side, Fidelity (FMR LLC) added 1.7 million shares as of September 30, reaching 5.65% of shares outstanding, while T. Rowe Price added 938,000 shares in the same period. BlackRock added 543,000 shares. The buying from large generalist funds into a stock that spent much of September near $100 stands in mild contrast to the insider selling at similar levels. One activist name on the register is Patrick J. Heron, who filed a Schedule 13D amendment in January 2026, the most recent update showing a 6.8% stake, down from 7.6% previously. As with all 13D/G disclosures, that stake is as last filed and positions below 5% may not trigger a new filing.

Medicaid reimbursement data from the Centers for Medicare and Medicaid Services adds some independent texture. Units reimbursed through Medicaid rose 268% on Q1 last year, and dollars reimbursed rose 123% on Q1 last year, both for the period ending January 2026. These figures cover Livmarli's early ramp and reflect the drug's real-world uptake in the government payer channel, though the dataset has not been measured as a leading indicator for Mirum's reported revenue figures, so they are context rather than a forward read on the November print.

The stock's recent history at earnings is worth keeping in view. The last reported result, in early August, produced a one-day drop of nearly 10% and a five-day loss of around 5%. The prior event similarly closed lower. With earnings now twelve days away, the width of the analyst target range ($130 to $200), the 13% short interest, and the gap between the current price and the mean target together make the November 2 release the clearest near-term reference point to watch.