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

AST SpaceMobile (ASTS) declined by 11% premarket, following a 10% increase from Monday's session. AST SpaceMobile reported a wider Q1 loss.

Sandisk (SNDK) was down 3.2% in pre-bell activity, after a 1% decline from the previous session.

Micron Technology (MU) fell by 2.3% hours before market open, swinging from a 6.5% increase at Monday's close.

Rocket Lab (RKLB) was 2.2% lower pre-bell, after an 11.2% increase from the previous session.

Advanced Micro Devices (AMD) was down 2.1% premarket, reversing a 0.8% increase from Monday's session.

Tesla (TSLA) declined by 1.3% pre-bell, swinging from a 3.9% rise at Monday's close.

Nvidia (NVDA) fell by 0.7% in premarket hours, following a 2% increase from Monday's session.

Microsoft (MSFT) was down 0.5% premarket, after closing Monday with a 0.6% decline.