For the second day in a row, the shares of US video game retailer GameStop Corp and movie theatre chain AMC Entertainment Holdings Inc have seen their prices soaring by more than 70% – and the reason is a single social media post. This is what market experts call a “meme rally”, involving retail market traders flocking into “meme stocks”, buying up the shares of companies with cult-like social media followers. They hit the ‘buy’ button based on sympathy or trends on social media, rather than profit, income or any other indicator of how the investment is about to perform. Following a relatively…