The financial services startup co-founded by Jack Dorsey and Jim McKelvey was Square.
The company began in 2009 after glass artist Jim McKelvey struggled to accept a credit-card payment for a sale. McKelvey and Twitter co-founder Jack Dorsey developed a small card reader that plugged into a mobile device, allowing individuals and small businesses to process payments without traditional point-of-sale equipment.
Square expanded beyond its original reader into software for sales, inventory, invoices, payroll, banking, and business lending. Its simple setup helped bring card acceptance to merchants that previously found payment systems expensive or cumbersome.
In 2021, Square, Inc. changed its corporate name to Block, Inc., while Square remained the name of its seller-focused business. That later corporate name can cause confusion, but the quiz asks about the startup’s original identity and its founding-era answer is Square.