One quarter, one question — discrete patent shock, or first slice of a four-product cliff?

• The print. Q1 2026 U.S. companion-animal organic revenue fell 11% as Convenia and Cerenia (combined ~$400M run-rate) drew U.S. generics on composition-of-matter expiry. Reported revenue grew 2.9%; strip the Fiscal Year Alignment pull-forward and underlying organic was roughly −5%.
• The stack. Four of the top-five products — 42% of FY2025 revenue — face simultaneous attack through 2028. Apoquel formulation patents roll into Elanco's Zenrelia; Simparica Trio meets Merck's once-yearly Bravecto Quantum (FDA-approved July 2025); Librela fell 16% in FY2025 under a safety overhang.
• The empirical curve. Industry erosion is severe but bounded — Draxxin lost 66% over five years, Rimadyl chewable 39% — yet through that last cycle total revenue still compounded mid-single-digit and operating margin marched 31% → 37.5%. Whether four stacked cliffs compound to the same shape is the underwriting question.

Record margins, record returns, record gross margin — printed the same year revenue grew 2%.

Operating margin compounded from ~17% to 37.5% over the last decade as mix tilted toward companion-animal therapeutics and biologics; gross margin set a new high at 71.8% and free cash flow cleared $2.28B (24% of sales). Quality held; growth slowed. The multiple compressed faster than either — and the bull's edge sits in that gap.

A 21.5% one-session reset on a guide set 84 days earlier.

Before. Through 2024, Zoetis sold one story: above-market growth every year, through every cycle. Revenue compounded 7.9% over 16 years; consensus was beaten in 19 of 20 quarters; the stock traded at 30–40× earnings.

Pivot. On May 7, 2026, the company missed Q1, cut FY2026 guidance 84 days after setting it, and printed −11% U.S. companion-animal organic. Shares fell 21.5% on 6.6× average volume; follow-on session (May 8) put $1.42B through the tape, the largest single-name turnover in the U.S. market that day. Five plaintiff firms opened securities-fraud investigations within a week.

Today. Stock at $80, down 68% from peak. Three directors bought $886K at $75–78 the week after the print; CEO Peck sold $2.54M at $127 on February 17 under a 10b5-1 plan. The next two prints — August 4 and early November — are when the bull/bear hinge resolves.

The $149 sell-side target is stale carry — the right anchor looks like 11–14× specialty-pharma-in-LOE, not 18–23× compounder.

• The bridge math doesn't pencil. The new $9.68–9.96B FY2026 revenue guide implies a 2H reacceleration to 5–7% organic — against Convenia/Cerenia generics now live, Apoquel patents rolling, Bravecto Quantum ramping, and Elanco's Zenrelia at trailing-blockbuster pace. A second guide cut at Q2 looks more likely than the $130–190 PT band implies.
• Top-5 concentration has been 42% for three years running. Lifecycle innovation has refilled the same buckets, not built new ones. Librela — the only widening segment — printed −16% last year under a safety overhang. The diversification that would justify a compounder multiple is not visible in the data.
• The 25.6% ROIC is mechanically lifted. Over $7B of cumulative buybacks has pushed tangible book equity to −$434M and shrunk the invested-capital denominator faster than EBIT grew. Strip the financial engineering and underlying ROIC sits closer to 18–20% — still a moat, but a different multiple lens.