Glaukos Carries the Heaviest Short Position in Its Peer Group After Q3

GKOS is the most shorted name in its ophthalmology cohort, with short interest at 8.3% of free float, a level its closest peers do not come close to matching.

Among the names most correlated to Glaukos, STAA gained 8.2% over the past week and SIBN 4.4%, both broadly in line with GKOS's 4.5% weekly advance. COO and BVS lagged, up just 1.3% and 3.4% respectively. None carries a short position comparable to Glaukos. BLCO added 4.1% on the week, also without the short overhang. The sector move looks broadly shared, which makes Glaukos's continued short build notable rather than a simple momentum story.

The short position has climbed without pause since mid-September. From around 3.9 million shares on September 16, the count reached 4.75 million by October 27, a 20% rise over the past month and now at its highest level in at least a year. The weekly gain of 4.6% in short interest mirrors the stock's own weekly price gain almost exactly, meaning shorts have added as the stock rose rather than covering into strength. Borrow is cheap, at 0.40% cost to borrow, down 15% on the week, and availability is deep at 901%, so there is no constraint on further shorting and no mechanical squeeze pressure. The put/call ratio of 6.05, while slightly above its 20-day average of 4.55, reflects a structurally elevated options skew that GKOS tends to carry rather than a fresh spike in defensive positioning.

The Street is broadly constructive, with most recent analyst moves pointing in one direction. Targets were raised heading into the print, with BTIG lifting to $205 earlier this month and Jefferies moving to $210 in late September. The consensus mean sits near $199, against a current price of $181.17. The debate is not about the core franchise but about Medicare reimbursement. The iDose TR device is the growth engine, and proposed LCD restrictions could require patients to fail medical therapy and prior laser treatment before qualifying, a setup that would delay adoption and, by some estimates, hit 2027 Medicare fee-for-service volumes by around 25%. Bulls point to real-world data showing roughly 60% of iDose procedures already involve prior SLT, suggesting the installed base is more resilient to a tighter LCD than the bear case implies. The EV/EBITDA multiple of 234x reflects a valuation built on a growth story, not current earnings, and the price-to-book of 12.9x has expanded around 1.4 points over the past month as the stock ran.

One mechanical tailwind worth noting is structural. ORTEX puts the probability of GKOS leaving the Russell 2000 at 80%, with a rank date of October 30 and a potential trade date of December 11. An exit from the Russell 2000 would bring an estimated $1.4 billion of index-tracker selling, roughly 8.7 days of normal volume. At the same time, ORTEX puts the odds of joining the Russell 1000 at 80%, which would bring $523 million of buying. The net flow is negative if both happen, but the critical price is $167.08 for Russell 1000 entry, already below the current price. For the S&P MidCap 400 addition, ORTEX puts the probability at 49%, with the stock currently trading 25% above the entry threshold; the December 4 announcement would be the date to watch for that outcome. In past Russell small-to-large migrations, the median move from announcement to effective was minus 3.6%, with trade-day volume running at 6.4 times normal.

The picture heading into the post-earnings session is one of a stock where short sellers built positions into strength, borrow conditions remain too easy to force any covering, and the next substantive data point is the Medicare LCD finalization, which will determine whether the iDose volume assumptions embedded in analyst targets hold.