Merck & Co.vs.Zoetis
MRK vs ZTS · both in Big pharma, part of the Medicine, pharma & life science value chain: Large, diversified pharmaceutical groups with broad portfolios across therapeutic areas.
Merck & Co. is about 11× larger than Zoetis by market cap; Zoetis trades at the lower P/E (11.5 vs 103.9); year to date, Merck & Co. leads (+43.1% vs −38.7%).
Side by side
| MRK | ZTS | |
|---|---|---|
| Market cap | $330B | $30.2B |
| Price | $156.45 | $77.29 |
| Today | +3.8% | +0.2% |
| Return YTD | +43.1% | −38.7% |
| Return 1Y | +72.4% | −50.7% |
| P/E | 103.9 | 11.5 |
| P/S | 5.0 | 3.2 |
| P/B | 7.2 | 9.6 |
Data as of 2026-08-26 · updates daily after U.S. close
The two companies
Merck & Co.MRK
Keytruda is the centre of the oncology business, which sits next to a substantial vaccines portfolio. Animal health forms a third division.
Full MRK profile →ZoetisZTS
Spun out of Pfizer in 2013 to sell animal medicines and vaccines. Simparica handles parasites while Librela and Solensia treat pain, with pets on one side of the business and livestock on the other.
Full ZTS profile →More MRK & ZTS comparisons
Other head-to-heads in the Big pharma segment.