GameStop, AMC shares jump another 40% in premarket trading as meme stock craze returns

Shares of GameStop and AMC surged around 40% in premarket trading on Tuesday, on track to extend gains after "Roaring Kitty," the man at the center of the meme stock craze, posted online for the first time in roughly three years.

Shares of both companies have since pared gains to roughly 35% at 04:35 a.m. E.T.

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