American Eagle Outfitters saw its stock surge 12% after announcing actress Sydney Sweeney would star in a new ad campaign. The “memestock” frenzy added $228m to its market value. Memestocks like GameStop have seen surges driven by social media hype, not financial performance, creating a “gamblified” stock market culture.

Read more at Yahoo Finance: Sydney Sweeney just sent this American stock soaring