Pre-market price movements and significant market activity for Merck & Co., Inc. ($MRK). Each move is flagged by Z-score statistical significance — showing when $MRK moved beyond its typical daily range. 3 significant moves detected in the last 30 days.
Current Market State
What May Be Driving MRK?
Vaxcyte's positive Phase 3 results for VAX-31 threatened Merck's vaccine market share.
Merck & Co., Inc. operates in the Healthcare sector, specifically Drug Manufacturers - General. Sector-wide movement can contribute to individual stock volatility.
Recent Unusual Moves (30 days)
| Date | Session | Price | Move | Z-Score | Rel. Vol. |
|---|---|---|---|---|---|
| Oct 5, 2026 | Regular | $139.62 | -3.25% | -2.68 | 1.0× |
| Sep 30, 2026 | Regular | $145.73 | -2.38% | -2.26 | 0.6× |
| Sep 30, 2026 | After-hours | $145.46 | -2.56% | -2.43 | 1.1× |
About MRK Premarket Movers
This page tracks unusual market activity for Merck & Co., Inc. (MRK) across all trading sessions — pre-market (4:00 AM–9:30 AM ET), regular hours (9:30 AM–4:00 PM ET), and after-hours (4:00 PM–8:00 PM ET). A move is flagged as "unusual" when its Z-score reaches 2 or higher, meaning the price change is statistically significant relative to MRK's recent daily volatility.
Z-score is calculated by comparing each move to the 20-day average return and standard deviation. A Z-score of 2.0 means the move is 2 standard deviations beyond the average — occurring in roughly the top 5% of daily moves. Relative volume (RVOL) compares current volume to the 20-day average volume at the same time of day, helping distinguish genuine institutional activity from noise.