SELX, the Nasdaq-listed Semilux International, has shed nearly 40% in a single week — dropping to $0.24 — while its borrow market tightens to levels that make new short positions increasingly expensive to establish.
The lending picture is the most striking feature here. Availability has contracted to just 23% of short interest, meaning there are fewer than one share available for every four already borrowed. That is deep inside "very tight" territory. Cost to borrow has climbed to 322% annually, roughly double where it was in early March — and up nearly 97% over the past month. The borrow has stayed stubbornly elevated throughout April and into May, rarely dipping below 250%, making the carrying cost alone punishing for anyone holding a short position through the stock's decline.
Short interest itself is a relatively minor factor at this level. At 0.28% of the free float — barely 122,000 shares — bears have not built a large structural position. The absolute shares short have actually fallen 31% over the past week, pulled back from a mid-April peak that was nearly four times the current level. The pattern in the history is worth noting: short interest ballooned from roughly 87,000 shares on March 27 to over 534,000 by April 6, then unwound sharply. Much of that unwind came before the worst of this week's price drop, suggesting shorts were covering into the move rather than adding to it.
The ORTEX short score of 61 sits in the middle of its recent range and has been broadly stable over the past ten days — no sharp acceleration despite the price collapse. The days-to-cover rank (97th percentile) and utilization rank (3rd percentile) from factor scores reflect the combination of a near-empty lending pool relative to shares already out on loan and a tiny float. Availability has been near or at its annual tightest on multiple occasions in April. When shares are this scarce to borrow and the stock is moving violently, the borrow becomes the story rather than the short interest level itself.
Ownership is heavily concentrated. The two largest holders — Yung-Peng Chang and Chih-Feng Wang — together control roughly 52% of shares outstanding, with no change reported since October. That kind of insider concentration limits the effective tradable float significantly and amplifies price moves in either direction. Meteora Capital and Millennium Management hold small institutional stakes; Millennium trimmed slightly as of end-December. No meaningful institutional accumulation or distribution is visible in the recent data.
An earnings event is scheduled for May 15. The most recent comparable print, on April 15, produced a one-day gain of 8.9% and a five-day follow-through of nearly 25%. Before that, the November 2025 release triggered a 37.8% five-day decline. The stock's reactions to results have been wide and inconsistent, which makes the May 15 event particularly relevant context for anyone watching the borrow market: with availability this tight and cost to borrow above 300%, the mechanics of covering or initiating around an event are materially constrained. What to watch is whether availability loosens ahead of the May 15 date — or tightens further as the event approaches.
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