SUPN Retail Buzz and Borrow Costs Rise as Acquisition Close Nears

Supernus Pharmaceuticals is drawing unusual attention across multiple signals as its agreed takeover by Indivior approaches its final stages. Retail attention hit 7.3 standard deviations above its 90-day average on 19 October, measured by Wikipedia pageviews and ORTEX stock page traffic. Cost to borrow has also jumped sharply over the past week, even as options traders have grown less defensive.

Acquisition Mechanics Driving the Borrow

The most concrete backdrop here is the pending deal. ORTEX forecasts an 84% probability that SUPN will be deleted from the Russell 2000 and Russell 3000, with an estimated announcement date of 26 October and a trade date of 30 October. The S&P SmallCap 600 deletion probability stands at 80%. These dates are ORTEX estimates, not confirmed by index providers.

Cost to borrow jumped to 0.75% as of 21 October, up 86% in one week and 62% over the past month. That is still a low absolute level, but the direction and pace matter. Availability remains very loose at 4,594%, meaning there is no shortage of borrowable shares relative to positions already on loan. The borrow-cost move is not a squeeze. It reflects fresh demand for short exposure, likely from arbitrageurs managing deal-spread risk as the close nears.

Short interest stands at 8.82% of free float, up 4.2% over the past week and 10.2% over the past month. At nearly 9% of float, that is a meaningful position. Among SUPN's closest peers by correlation, INDV itself is the most obvious comparator: as the acquirer, its own short interest dynamics run in the opposite direction to SUPN's deal-spread positioning.

Options Traders Less Defensive

The put-call ratio fell to 3.84 on 21 October, down from a 20-day mean of 4.29. That puts it 2.24 standard deviations below its recent average. The absolute PCR is still well above 1, meaning puts dominate the book heavily. But the shift toward calls at the margin is consistent with traders pricing a higher probability that the deal completes on the terms agreed.

The next earnings event is logged for 29 October, the same week as the estimated index announcement date. That confluence makes the final days of October the critical window to watch.

Retail Attention Spike

Wikipedia pageviews and ORTEX stock page traffic combined to produce a reading 7.3 standard deviations above the 90-day average as of 19 October. This is an attention measure, not a revenue or earnings indicator. Retail attention spikes of this magnitude on acquired companies typically track coverage of the deal timeline rather than underlying business developments. None of SUPN's alt data datasets have a measured lead on its financials, so no predictive signal can be drawn from the attention move.

Medicaid reimbursements for SUPN drugs were up 11% on the same quarter last year as of the Q1 2026 period, per Centers for Medicare and Medicaid Services data.

Data Summary

• Short interest: 8.82% of free float, up 4.2% in one week
• Cost to borrow: 0.75%, up 86% in one week
• Availability: 4,594%, loose
• Put-call ratio: 3.84, down 2.24 standard deviations from its 20-day mean
• Retail attention: 7.3 standard deviations above 90-day average (as of 19 October)
• ORTEX index deletion forecast: 84% for Russell 2000 and Russell 3000 (estimated trade date 30 October)
• Analyst consensus price target: $60.50 against a last close of $41.21