Keith Gill, nicknamed 'Roaring Kitty', has posted on the social media platform X after nearly three years.
Since Sunday, Gill has shared more than 10 clips from movies, including "X-Men Origins: Wolverine" and "The Avengers".
Following Gill's posts, GameStop shares rose by as much as 51 percent in pre-market trading, while AMC shares increased by as much as 58 percent.
According to J.P. Morgan data, both GameStop and AMC were the most traded stocks by retail investors on Monday.
MARKET VALUE INCREASED
GameStop rose by as much as 118 percent on Monday, closing at its highest level in two years, and its market value increased from approximately 4 billion dollars to 9.32 billion dollars.
AMC also rose by 78 percent to 5.19 dollars. The world's largest cinema chain has more than doubled from its record low in mid-April.
News Source: 12punto