The most-talked-about stocks in the Reddit subforum Wallstreetbets were mostly lower hours before Tuesday's opening bell.

Sandisk (SNDK) fell by 3.3% premarket, after closing Monday with a 5.3% drop.

Rocket Lab (RKLB) was down 2.5% in premarket hours, swinging from a 5.1% increase at Monday's close.

Poet Technologies (POET) fell by 2.1% in pre-bell activity, following an 11% decline in the previous session.

Micron Technology (MU) was 2% lower hours before market open, after a 6% decrease Monday.

AST SpaceMobile (ASTS) declined by 1.7% pre-bell, swinging from a 3.8% rise in the previous session.

Nvidia (NVDA) was down 0.8% premarket, following a 1.3% fall Monday.

ServiceNow (NOW) rose by 4.4% in premarket activity, after an 8.8% increase in the previous session.

Microsoft (MSFT) advanced by 0.6% pre-bell, following a 0.4% increase at Monday's close.