Three lending signals converged on the XLB Materials Select Sector SPDR in the space of 48 hours. Short interest jumped. Availability collapsed. The borrow cost climbed. All three are moving in the same direction at the same time.
Availability has dropped to just 9.7% — down from 188% as recently as May 27. That is an extraordinary move in five trading sessions. For every share currently borrowed short, fewer than one in ten remains available to lend.
The 52-week low for availability sits at 3.85%. The current reading is closing in on it.
Cost to borrow has risen 27% over the past week to 0.69% annualised. That remains low in absolute terms. But the direction — and the speed — matters here. The CTB spiked to 1.02% on May 29 before easing slightly. The lending desk is repricing.
SI % FF stands at 22.0% of free float as of June 1. That is up 15.5% in a single week. It is also the highest reading since late April, when it was tracking above 16 million shares.
The monthly picture provides context. Short interest peaked near 18.2 million shares on April 23. It then fell sharply through mid-May, bottoming around 10.9 million shares on May 25. This week's rebuild has been aggressive — 12.6 million shares and rising.
The ORTEX short score sits at 61.6 out of 100, its highest point in the trailing ten-day window.
Several large holders reported meaningful position changes in the most recent 13F cycle (Q1 2026). BNP Paribas added 4.7 million shares. Wells Fargo added 2.9 million. Citadel added 2.5 million. Bank of America added 2.5 million.
Marshall Wace entered with a fresh 2.1 million-share position — building from zero.
On the other side, Morgan Stanley trimmed 361,703 shares and Goldman Sachs cut 501,895. The net institutional picture is mixed, but the fresh long positioning from several names runs directly against the short rebuild in the lending market.
Availability at sub-10% with short interest still climbing is an unstable configuration. Any further demand for borrows will either be turned away or priced sharply higher. The May 19–21 episode — when availability touched 4.8% and utilisation hit 100% — resolved with a rapid short unwind. Whether this week's rebuild repeats that pattern or pushes availability to a new 52-week low is the key variable to track.
Data summary
See the live data behind this article on ORTEX.
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