Three signals converged on ABUS overnight. The borrow market has tightened dramatically, short interest has surged, and options traders are leaning bullish. The ORTEX short score hit 90.2, up from 58.6 two weeks ago.
The cost to borrow ABUS shares stood at 0.59% on September 28. By September 30 it had reached 53.6%, a record high and a near-9,000% rise in two days. That kind of move does not happen without a sudden, concentrated rush to establish short positions.
Availability tells the same story. Two weeks ago, shares available to borrow were running at roughly 789% of short interest, a loose market with plenty of supply. By September 30 that had collapsed to 35.5%. For every share currently borrowed, fewer than four-tenths of a share remain available. The lending pool is effectively under stress.
ABUS short interest hit 13.5% of free float as of September 30, up 40% from the prior week and up 51% over the past month. That puts it firmly in territory where positioning matters. Days to cover stands at 5.0 according to the latest FINRA fortnightly data, so unwinding the position would take meaningful time if the stock moved against shorts.
The ORTEX short score, which aggregates lending-market signals, closed at 90.2 on September 30. It was at 58.6 on September 18. A 32-point move in less than two weeks is extreme, and the score is now at the 0th percentile for days-to-cover rank and 11th percentile for availability, both pointing to a constrained borrow environment.
Against that backdrop, options positioning moved in the opposite direction. The put-call ratio dropped to 0.80 on October 1, down from 0.99 the prior session and 2.1 standard deviations below the 20-day mean of 0.92. Call volume is outpacing puts. That divergence between options flow (net bullish) and short positioning (aggressively bearish) sets up a tension worth watching.
Roivant Sciences holds 20.5% of the class as last disclosed per a Schedule 13D/A filed in February 2025. Whitefort Capital, also flagged as a 13D filer, reported an 8.0% stake as recently as September 4. Both positions are "as last disclosed" and may have changed since filing. The presence of two activist-flagged holders limits the float available to borrow, which helps explain how the lending market tightened so sharply on a relatively modest increase in short demand.
Earnings are scheduled for November 12. The next six weeks will test whether the borrow squeeze or the bullish options flow proves the better read on Arbutus.
Data summary
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