NBIX Short Interest Climbs to Yearly High Before Q3 Results

Short interest in NBIX has reached its highest level in at least a year, with 6.45 million shares short as of October 29, equal to 6.5% of the free float. That figure has risen 8.5% over the past week and 16.5% over the past month, a sustained build rather than a one-day spike. Borrow conditions remain loose: availability at 2,494% means shares to lend comfortably outnumber existing short positions, and the cost to borrow has actually fallen, down roughly 21% over the past month to 0.38%. Options positioning is calm, with the put/call ratio at 0.51, barely above its 20-day average and well off the 52-week high of 1.76. The stock closed at $146.10 on October 30, up 2.4% over the past week, but that lagged the median weekly gain of 4.2% among its closest correlated peers, including KRYS and EXEL, which each rose more than 6%.

The debate among analysts centers on whether Ingrezza's growth trajectory and the Crenessity launch can absorb two structural pressures: slower tardive dyskinesia market penetration and the IRA Maximum Fair Price mechanism, which bears estimate will lift gross-to-net deductions on Ingrezza to 28.7% from 19.6% by 2029, cutting that year's revenue estimate from $3.4 billion to $3.0 billion. BMO Capital trimmed its target to $150 from $164 on October 12, the most cautious recent move, reflecting those margin concerns. Elsewhere, the direction has been more constructive: Guggenheim assumed coverage with a $207 Buy target on October 6, and UBS, while lowering its target to $214 from $231, held its Buy rating. The consensus mean target of $206 sits roughly 41% above the current price, a wide implied return that reflects genuine disagreement rather than straightforward conviction. The bull case rests on Q2 revenue of $959 million growing 39% year on year, a pipeline with around 10 readouts expected in 2027, and Crenessity's Q3 sales tracking ahead of the $201 million consensus estimate at approximately $210 million.

Medicaid reimbursement data from the Centers for Medicare and Medicaid Services offers a separate read on commercial uptake. In Q1 2026, Medicaid dollars reimbursed for Neurocrine's drugs rose 41% against the same quarter a year earlier, and Medicaid units reimbursed rose 22% over the same comparison. None of the alt data series covering this company has been measured to lead reported revenue, so these figures describe Medicaid channel activity rather than foreshadowing the print.

The insider register is quiet ahead of the report. The only open-market activity in the past 90 days was a pair of planned sales by the CFO and Chief Corporate Affairs Officer in mid-September, both executed under pre-arranged 10b5-1 plans and totalling less than $500,000 combined. Grants and tax withholding account for the remaining activity, leaving net 90-day insider flows at roughly negative $7.9 million in value terms, but almost entirely compensation mechanics rather than discretionary conviction. On the ownership side, JPMorgan Chase filed a 13G/A on October 15 reporting its stake had fallen to 5.2% from 6.3%, and a new 13G from Vanguard Portfolio Management was filed October 30, disclosing a 5.0% position. No 13D activist is on the register. As always with 13D/G filings, stakes are as last disclosed around the 5% threshold and holders can exit that level without further notification.

NBIX has fallen between 7.7% and 10.4% in the session following each of the last two earnings prints. The Q3 report will test whether Q3 Crenessity sales and updated Ingrezza guidance can interrupt that pattern, and whether the short interest build over the past month reflects a well-founded concern or a position that unwinds sharply on delivery.