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

Bloom Energy (BE) was 6% higher premarket, after a 7.4% increase from Friday's session. The company will join the S&P 500, effective Sept. 21.

Oracle (ORCL) was up 3.8% premarket, after a 3.1% increase from the previous session.

Micron Technology (MU) advanced by 2.1% in pre-bell hours, following a 6.1% increase at Friday's close.

Sandisk (SNDK) rose 2% pre-bell, after closing Friday with an 11.9% increase.

Nvidia (NVDA) was 0.6% higher in premarket activity, following a 0.8% increase from Friday's session.

Alamos Gold (AGI) was down 0.9% premarket, after a 1.9% decline from the previous session.

Apple (AAPL) was 0.4% lower hours before market open, after closing Friday with a 2.5% decline.

Lululemon Athletica (LULU) declined by 0.3% pre-bell, following a 17.4% fall at Friday's close.