The pre-market is where overnight news, foreign listings, and earnings released before the bell get priced. Liquidity is a fraction of regular hours and is concentrated in the final 30 minutes, so an early print on 200 shares is not a price in any meaningful sense.
Practical constraints matter. Most brokers accept only limit-order types, a stop-order usually will not trigger, and orders route to a single venue rather than across the whole market. Pre-market highs and lows are also excluded from many chart defaults.
Example: a stock closes at $30 and reports after a pre-market release. It trades $34.20 at 05:15 on 900 shares, drifts to $32.40 by 09:00 on 180,000 shares, and the opening-auction prints $31.85 on 2.4M shares.
Related: after-hours-session, extended-hours, opening-auction, earnings-report, limit-order