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

Nebius Group (NBIS) rose by 50% in pre-bell hours, reversing a 2.2% decline from the previous session. Nebius signed a multi-billion dollar commercial agreement to provide Microsoft (MSFT) access to dedicated graphics processing unit infrastructure capacity at its new data center in Vineland, New Jersey, over a five-year term.

Nvidia (NVDA) was up 0.8% pre-bell, following a 0.8% increase at Monday's close.

Tesla (TSLA) advanced by 0.4% premarket, swinging from a 1.3% decline in the previous session.

UnitedHealth Group (UNH) was 0.1% higher in pre-bell hours, following a 1.5% increase Monday.

Planet Labs (PL) was down nearly 12% premarket, swinging from a 48% jump in the previous session.

AST SpaceMobile (ASTS) declined by 2.7% in premarket activity, after closing Monday with a 3.9% drop.

Opendoor Technologies (OPEN) fell by 2.5% hours before market open, following a 9.2% decline at Monday's close.

Robinhood Markets (HOOD) was down 0.5% premarket, swinging from a 16% increase in the previous session.