SI-BONE heads into the back half of September with short sellers quietly adding pressure on a stock that has lost ground for three consecutive months, even as every analyst with a published rating is telling clients to buy.
The short interest story is the central tension here. Bears have added steadily — short interest climbed from roughly 4.9 million shares in mid-August to 5.56 million by September 10, lifting the position to 12.8% of the free float. That is a meaningful level for a small medical device company. The move has been gradual rather than dramatic, building week after week through August. The ORTEX short score has settled in the high 60s — a reading that ranks the stock in the 7th percentile for short score across the universe, flagging it as one of the more heavily shorted names in its peer group. Days to cover sits near 9.9 based on the most recent FINRA fortnightly data, which means an unwind would take the better part of two weeks at normal trading volumes.
The borrow market tells a less alarming story. Despite the elevated short interest, availability is loose — roughly 4.4 shares remain available to borrow for every one already lent out. That reading, while slightly tighter than a month ago when availability was above 550%, still points to plenty of capacity for new shorts to enter without driving a borrow squeeze. Cost to borrow is negligible at 0.58%, barely moving over the past month. Options positioning has swung firmly to the bullish side: the put/call ratio has collapsed to 0.18, well below its 20-day average of 0.43. Call volume has overwhelmed puts over the past several weeks, a sharp reversal from the 1.03 reading that persisted through most of August.
Analysts are firmly in the bull camp, though that conviction was tested earlier in the year. After targets were cut across the board in May — Truist and TD Cowen both lowered to the high teens — the August earnings report prompted a reset. UBS initiated coverage in late July at Buy with a $24 target, then raised it to $25 after the print. Truist lifted to $23 from $21, and TD Cowen moved to $20 from $18. The consensus mean target of $25 implies roughly 36% upside from the current $18.38. The bull case rests on the Smith & Nephew partnership broadening distribution, a growing sales force targeting 100 territories within 12 months, and improving EBITDA trajectory. Bears point to the premium valuation — EV/EBITDA near 39.5x on a company still running operating losses — and dependence on reimbursement rates for its sacropelvic fixation procedures, where DRG code adoption has been slow. The price-to-book multiple has been compressing, down from a 30-day high, consistent with a market that is not re-rating the stock despite the analyst enthusiasm.
The most notable institutional move is at the top of the holder register. First Light Asset Management holds 18.1% of shares, a position that increased by 2.77 million shares in the most recently reported quarter. Cadian Capital Management, a hedge fund, filed a fresh Schedule 13G in August disclosing a 7.5% stake — a first-time filing — suggesting a new concentrated position was built through the summer. Meanwhile, several passive holders — including a Vanguard entity and OrbiMed — have dropped below the 5% disclosure threshold without replacement filings, reflecting some natural turnover in the register. All 13D/G stakes are as last disclosed around the 5% threshold; holders dropping below may exit without a further filing. Insider sales over the past 90 days have run to roughly $3.5 million net, driven by pre-arranged 10b5-1 plan disposals from the CEO and CFO in August — planned sales, not discretionary conviction signals.
The last earnings print on August 3 produced a 3.8% one-day gain and a 6.1% five-day move, a constructive reaction that helped reset analyst targets higher. The next event is not until November 9, leaving roughly eight weeks for the market to resolve the current contradiction: short sellers have built a 12.8% float position while every covering analyst maintains a Buy rating, call buyers have returned in force, and a new concentrated hedge fund holder just appeared on the register. The key variable to watch between now and November is whether revenue guidance on the Smith & Nephew ramp holds — that is the single data point most likely to close the gap between where shorts and bulls are positioned.
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