Square is a financial technology company founded in 2009 by Jack Dorsey and Jim McKelvey that initially revolutionized small business payments with its iconic white card reader that plugged into smartphones and tablets. The company has since expanded into a comprehensive ecosystem of financial services including point-of-sale systems, business loans, payroll services, and online payment processing for businesses of all sizes. Square went public in 2015 and later rebranded its parent company to Block in 2021, while continuing to operate Square as its primary business-focused brand alongside other ventures like Cash App and Tidal.