Pre-market price movements and significant market activity for BERKSHIRE HATHAWAY Class B ($BRK.B). Each move is flagged by Z-score statistical significance — showing when $BRK.B moved beyond its typical daily range. 1 significant move detected in the last 30 days.
Current Market State
What May Be Driving BRK.B?
No specific catalyst has been identified in the available market data for BERKSHIRE HATHAWAY Class B (BRK.B). The moves shown below are flagged based on statistical significance (Z-score ≥ 2), meaning BRK.B moved beyond its typical daily range. A catalyst may exist — such as earnings, analyst action, sector momentum, or news — but has not yet been tagged to this ticker.
BERKSHIRE HATHAWAY Class B operates in the Financial Services sector, specifically Fire, Marine & Casualty Insurance. Sector-wide movement can contribute to individual stock volatility.
Recent Unusual Moves (30 days)
| Date | Session | Price | Move | RVOL |
|---|---|---|---|---|
| Sep 21, 2026 | After-hours | $502.89 | -1.35% | 1.0× |
About BRK.B Premarket Movers
This page tracks unusual market activity for BERKSHIRE HATHAWAY Class B (BRK.B) 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 BRK.B'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.