Square stocks plummet 4% in Monday’s premarket due to concerns that it is overpaying for the Australian payments group Afterpay. Afterpay (ASX:APT) stock jumped 19% to A$114.80 (approximately $84.4) in Monday's trading in Sydney. The all-stock deal values the ‘buy-now, pay-later’ platform at $29 billion and is aimed to make the combined entity a key global payments company. Under the deal, Afterpay shareholders will receive a fixed exchange ratio of ...