IDXX vs ZTS: Which Is the Better Buy in 2026?
Last updated August 2026
Short answer
IDXX and ZTS are similarly sized, but ZTS trades noticeably cheaper on forward earnings (10.46x vs 32.91x): the market is paying up for IDXX's profile and pricing ZTS more conservatively, or for faster growth. Which you prefer comes down to the drivers you believe, and whether adding either over-concentrates what you already own.
IDXX vs ZTS: the tie-breaker metrics
Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.
| Metric | IDXX | ZTS | What it tells you |
|---|---|---|---|
| Forward P/E | 32.91 | 10.46 | Valuation on next year's expected earnings, the same yardstick for both. Lower is cheaper for that growth; higher means the market is paying up. |
| Trailing P/E | 38.77 | 12.67 | Valuation on the last 12 months. A big drop from trailing to forward means the market expects earnings to jump, so more growth is already in the price. |
| Beta | 1.54 | 0.75 | Volatility vs the market. Above 1 swings harder than the index; below 1 is steadier. Higher beta means bigger drawdowns to hold through. |
| Price vs 52-week range | 13% of range | 7% of range | Where today's price sits between the 52-week low and high. Near the high is momentum with less margin of safety; near the low is out of favor or a discount, depending on why. |
Reading it: ZTS is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.
Before you buy: how IDXX and ZTS affect your concentration
The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. IDXX and ZTS share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.
This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined IDXX and ZTS exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.
What does IDEXX Laboratories, Inc. (IDXX) do?
IDEXX Laboratories (NASDAQ: IDXX) sells diagnostics to veterinarians. Its Companion Animal Group, roughly ~92% of revenue, places in clinic analyzers (Catalyst, ProCyte, SediVue and the newer inVue Dx) into practices and then sells the consumables those instruments burn through, while a global reference laboratory network runs the panels clinics send out. Practice management software and digital imaging (ezyVet, Cornerstone, ImageVue) sit alongside the diagnostics and pull more testing through the same customers. Two smaller segments round out the business: Water, which tests drinking water for coliform bacteria, and Livestock, Poultry and Dairy. The company is headquartered in Westbrook, Maine, employs about ~11,000 people, and sells into more than 175 countries.
What does Zoetis (ZTS) do?
Zoetis (ZTS) is the world's largest animal health company, developing and selling medicines, vaccines, diagnostics, and other products for both companion animals (pets like dogs and cats) and livestock (cattle, swine, poultry, and fish). Spun out of Pfizer in 2013, it holds leading positions across dermatology, parasiticides, pain, vaccines, and other categories, with well-known franchises such as Apoquel and Cytopoint for pet itch and allergic skin conditions, the Simparica line of parasiticides, and Librela for osteoarthritis pain in dogs. Companion animal products, driven by the long-run humanization of pets and rising spending on their care, have become the larger and faster-growing part of the business, while livestock provides a more staple, protein-demand-linked base. Zoetis sells through veterinarians in the United States and internationally, invests heavily in research and development to sustain its innovation pipeline, and benefits from patents, brand loyalty, and deep vet relationships. Headquartered in Parsippany, New Jersey, it is widely viewed as a defensive-growth leader on the structural trend of people spending more on animal health, though it faces cyclical pet-visit softness, pricing pressure, and rising competition.
IDXX vs ZTS: how do they differ?
Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.
- IDXX drivers: The CAG Diagnostics recurring annuity; inVue Dx and the premium installed base.
- ZTS drivers: Leader in a structurally growing market; Innovation-driven franchises and pipeline.
Which fits which kind of investor
A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: Visit volume is the central risk, because if US clinic traffic keeps eroding and testing per visit stops covering the shortfall, the recurring line decelerates toward mid single digits and a ~37x forward multiple has a long way to fall. For ZTS, zoetis faces near-term pressure from softer veterinary visit volumes and increased price sensitivity among pet owners, which have weighed on its companion-animal business and prompted trimmed guidance.
IDXX or ZTS: which should you pick?
IDXX vs ZTS: the full fundamentals
IDXX. At roughly ~$551 a share and a market cap near ~$43B, IDEXX trades at about ~39x trailing earnings and ~37x the midpoint of its own 2026 EPS guidance, and it pays no dividend. That is still a premium to the broader medical device group, though well below the high forties and fifties multiple the stock carried through much of the past five years, and the shares sit close to a 52 week low of ~$519 versus a high of ~$770. Free cash flow of ~$1.25B on ~$4.55B of trailing revenue is a ~28% free cash flow margin, which funded roughly ~$700M of repurchases in the first half of 2026 alone.
ZTS. Zoetis is valued as a high-quality, defensive-growth compounder, so it often trades at a premium price-to-earnings multiple relative to the broad market. In early 2026 it trimmed full-year guidance, citing softer pet-visit trends, price-sensitive pet owners, and competition, which pressured the stock. Livestock and international growth partly offset soft US companion-animal demand. Figures are approximate and change with each quarter and with currency movements; verify current numbers before relying on them.
Headline figures (approximate, August 2026): IDXX shows revenue (ttm) ~$4.55B, up ~13% year over year, cag diagnostics recurring revenue (q2 2026) ~$975M, up ~11%, about ~80% of total revenue, operating margin (q2 2026) ~35.0%, up ~140 basis points year over year, eps (ttm) and valuation ~$14.22 against a ~$551 share price, a ~39x trailing P/E; ZTS shows revenue (2026 guidance) ~$9.7 billion to $10.0 billion, q1 2026 revenue ~$2.3 billion, up ~3% year over year, adjusted eps (2026 guidance) ~$6.85 to $7.00, business mix companion animal (larger, faster-growing) plus livestock.
The bottom line: IDXX vs ZTS
IDXX and ZTS are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined IDXX and ZTS exposure against your real portfolio. It is not an investment adviser.
Wondering how IDXX or ZTS fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in IDEXX Laboratories, Inc. with AI
Connect the broker you already use and ask Walnut's AI how IDXX fits what you actually hold: whether you own it already through a fund, what it would do to your concentration, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What is the difference between IDXX and ZTS?
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IDEXX Laboratories (NASDAQ: IDXX) sells diagnostics to veterinarians. Zoetis (ZTS) is the world's largest animal health company, developing and selling medicines, vaccines, diagnostics, and other products for both companion animals (pets like dogs and cats) and livestock (cattle, swine, poultry, and fish). They show up together because they share investment themes, but they are different businesses, so the better fit depends on which thesis you are expressing.
Is IDXX or ZTS the better stock?
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Neither is universally better; they suit different views and risk levels. Walnut is informational, not investment advice. Compare what each does, the tie-breaker metrics above, and the risks, then decide which fits your thesis and what you already own.
Which is cheaper, IDXX or ZTS?
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On forward P/E (as of August 2026), IDXX trades at 32.91x and ZTS at 10.46x, so ZTS is the cheaper of the two on next year's expected earnings. A lower multiple is not automatically the better buy: a richer valuation can be justified by faster growth, and a lower one can reflect real risk. Weigh the multiple against how fast each business is compounding.
Should you own both IDXX and ZTS?
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Because they share themes, owning both concentrates you in that theme. That can be intentional (a focused bet) or accidental (less diversification than it looks). Walnut can show your combined exposure across both, and whether adding either over-concentrates you, before you buy.
What are the risks of IDXX vs ZTS?
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IDXX: Visit volume is the central risk, because if US clinic traffic keeps eroding and testing per visit stops covering the shortfall, the recurring line decelerates toward mid single digits and a ~37x forward multiple has a long way to fall. Wellness visits, down more than ~3%, sit at the discretionary end of veterinary spending and track consumer pressure and muted puppy adoption directly. Competition is intensifying from Mars owned Antech, which absorbed Heska and can now bundle in clinic analyzers with a national laboratory network the way IDEXX does, and from Zoetis in point of care instruments. Roughly ~23% of revenue is non US, so currency both flattered first half reported growth and now costs an estimated ~$15 million against the full year outlook. Leverage is not the concern, at ~$772 million of net debt against roughly ~$1.7 billion of adjusted EBITDA, but the ~28% drawdown from the 52 week high is a reminder of how fast this multiple reprices when the volume narrative wobbles. ZTS: Zoetis faces near-term pressure from softer veterinary visit volumes and increased price sensitivity among pet owners, which have weighed on its companion-animal business and prompted trimmed guidance. Competition is intensifying, including newer entrants and generics in key dermatology and parasiticide categories, and patent expirations can erode pricing over time. A large share of revenue comes from outside the United States, exposing it to currency swings and international regulatory and pricing risk. Livestock demand is tied to protein consumption, herd sizes, and disease outbreaks. As a premium-valued, high-quality name, the stock can carry an elevated multiple that leaves it vulnerable to de-rating if growth disappoints. It is a growth-oriented holding, not a deep-value or high-yield income stock.
Walnut is informational, not investment advice. This page is descriptive and not a recommendation to buy or sell IDXX or ZTS; figures are approximate and dated (as of August 2026). Verify current data before investing.