Tandem Diabetes Care arrives at the end of September with short sellers adding pressure, analysts cutting targets, and the stock down 27% from where it printed Q2 results in August.
Short interest is the clearest signal of mounting scepticism. At 18.9% of free float, it has climbed 9% over the past week and nearly 19% over the past month, a build that tracks almost exactly with the stock's slide from roughly $21 to $16.57. The FINRA fortnightly count, settled to September 15, put shares short at 12.47 million with a days-to-cover of 7.89, making any sharp reversal structurally difficult to sustain. The ORTEX short score of 59.5 keeps TNDM firmly in the elevated-conviction-short bracket, yet the borrow market itself tells a different story: availability is extremely loose at 1,080%, meaning there are more than ten shares available to borrow for every one already lent out. Cost to borrow has barely moved, holding near 0.52% annually. Short sellers face no squeeze pressure from the lending market. The position is being built into ample supply, which makes this a conviction trade rather than a mechanical or technical accumulation.
Options have edged more defensive over the week, though not dramatically so. The put/call ratio closed at 0.58 on Tuesday after spiking to 0.75 on Monday, both above the 20-day mean of 0.47 and at roughly 1.4 standard deviations above it. The 52-week high on PCR is 1.17, so current hedging is elevated but not at any extreme. The options picture corroborates a cautious but not panicked market.
The Street's direction of travel is clearly lower on targets, though most firms still hold positive ratings. Citigroup's Joanne Wuensch cut her target today to $20 from $24 while staying Neutral. Truist's Richard Newitter trimmed to $28 from $31 on September 24, keeping his Buy. Several other firms, including UBS, Mizuho, and Deutsche Bank, have moved targets lower through the summer. The mean price target across the Street is $28.35, roughly 71% above the current price of $16.57, but that gap reflects the recent slide rather than fresh bullishness. William Blair initiated with Outperform in August without a target, adding another name to the bull side.
The bull and bear cases are genuinely in tension here. Bulls point to the t:slim X2 and Mobi pump portfolio, a pharmacy-channel shift that the company argues lifts customer lifetime value from around $8,000 to $17,000, an over-150,000 out-of-US patient base representing a meaningful renewal opportunity, and a Mobi Tubeless patch pump slated for late 2026 FDA approval. Full-year guidance of $1.065 to $1.085 billion in revenue with a 56 to 57% gross margin implies a company that has turned a corner on execution. Bears focus on the near-term revenue distortion from the shift to a Pay/Go pharmacy model, where upfront shipments carry $0 of revenue and conversion is still early. The stock trades at roughly 1.3x EV/Sales, and the P/B multiple has fallen around 1.8 points over the past month. The EV/EBITDA of 12.9x is heading lower alongside the price, but profitability remains thin, with a deeply negative P/E reflecting ongoing losses.
Ownership gives some context on who is sitting with the pain. BlackRock added 892,000 shares through August to hold 16.6% of shares. Vanguard entities collectively hold another 11% or so, adding steadily. Sessa Capital, a smaller active manager, holds 7.3% and also added shares through June. First Light Asset Management added over two million shares to reach 4.9%, the largest percentage increase among the top holders. These are not fast-money flows. Voya Financial is notable on the other side, having cut its stake from 6.3% to 0.2% per its August filing, one of the sharper disclosed exits in the register. All 13D/G stakes are as last disclosed and holders can fall below 5% without a further filing.
The next earnings date is November 4, and the most recent print, Q2 in August, produced a one-day move of plus 14.2% and a five-day follow-through of plus 18.1%. The quarter before that saw a one-day fall of 7%. History shows TNDM can move sharply in either direction around results. With short interest near 19% of float, a seven-week wait until the print, and analysts still trimming targets despite broadly constructive ratings, the key question into November will be whether the pharmacy-channel transition is tracking ahead or behind management's own timeline.
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