AMPH: Options Spike Flags Caution Ahead of November Print

Amphastar Pharmaceuticals heads into its November 6 earnings with an unusual burst of defensive options activity against a backdrop of easing short interest and a stock that has quietly recovered nearly 11% in the past month.

The sharpest signal this week comes from the options market, where put demand has jumped to levels that stand well apart from recent norms. The put/call ratio hit 0.417 on Monday, more than four standard deviations above its 20-day average of 0.076. That average itself tells the story: for most of the past month, AMPH options flow was almost entirely call-dominated, making Monday's put-heavy session a genuine break in pattern. The reading is close to the 52-week high of 0.607, which was last touched in late September around the time the stock was under pressure near $24. This is the clearest sign that at least some traders are buying downside protection ahead of the November print.

The borrow market tells a quieter story. Short interest has fallen about 17% over the past month to 9.2% of the free float, roughly 4.2 million shares. Most of that reduction happened in early October, when short interest dropped from around 5 million shares to its current level in the space of a week. Cost to borrow is low at 0.48%, up about 46% on the week but in absolute terms barely above the general collateral rate. Availability is exceptionally loose, running at 516% of outstanding short interest, meaning lenders hold roughly five shares available for every one already borrowed. There is no squeeze pressure here and no evidence of aggressive new shorting. Positioning looks cautious at the options level rather than crowded at the borrow level.

The Street has been predominantly neutral on AMPH for most of 2026, and the analyst data here is stale: the most recent changes on record are from mid-August, when the mean price target was $22.50, below the current price of $26.14. That gap suggests the market has moved faster than analyst revisions following what were two consecutive positive post-earnings days, with the stock gaining around 2.5% to 2.7% on each of the last two results days. The bear case centres on Baqsimi pricing erosion, where rebates and 340B discounts have weighed on revenue despite rising prescription volumes, and on the 56% collapse in injectable glucagon after Viatris entered the market. Bulls point to intact Baqsimi peak sales guidance of $250 million to $275 million, early signs of traction from the ipratropium bromide HFA launch, and a valuation that remains undemanding: the trailing P/E sits near 8.3x, EV/EBITDA around 7x, and price-to-book just above 1.19x. The 90-day forward EPS momentum factor scores in the 79th percentile, a sign that revisions have been trending the right way even as the stock is rated in the 17th percentile on the short score rank, reflecting the still-meaningful short interest.

On ownership, the register is notable for founder concentration. Jack Y. Zhang holds 24.8% per the most recent 13G filing, and Applied Physics and Chemistry Laboratories holds another 16.1%. Together the founding-related bloc controls over 40% of shares. BlackRock holds 11.5% and Dimensional Fund Advisors added 277,000 shares in the most recent quarter, taking its stake to 5.4%. American Century was the most active institutional buyer last quarter, adding 302,000 shares. On the insider side, recent Form 4 activity has been modest and net negative: the 90-day net was minus 33,479 shares worth roughly $764,000, mostly from a Senior EVP exercising and selling in September and planned sales by the CFO under a pre-arranged 10b5-1 programme. None of these trades read as a directional signal.

With earnings on November 6, the next two weeks are about whether Baqsimi revenue stabilises, whether the ipratropium launch gains enough traction to offset the glucagon and epinephrine headwinds, and whether management updates its full-year growth guidance. Monday's options activity suggests at least part of the market is not taking the stock's recent recovery for granted.