Square started because a glassblower in St. Louis lost a $2,000 sale when he could not take a credit card. That glassblower was Jim McKelvey. His friend Jack Dorsey, a cofounder of Twitter, built a small white reader that plugged into a phone's headphone jack. Suddenly any small seller could take cards. Square filed to go public in October 2015, with Dorsey running both Square and Twitter at once.

A Lost Sale in St. Louis

Dorsey and McKelvey founded Square in 2009. The bet was that millions of small sellers had been shut out of card payments by contracts, fees, and bulky terminals. Square offered one flat rate and no long contract. The free reader came in the mail. Square then added software for small shops: point of sale, payroll, and loans. In 2013 it launched Square Cash, the app that grew into Cash App.

Priced Low, Rose Fast

Square priced at $9 a share on November 18, 2015, below its expected range of $11 to $13. Its stock rose 45 percent the next day to close at $13.07 on the New York Stock Exchange. Cash App became as large as the seller business. In December 2021 the company renamed itself Block. In 2025 its ticker changed from SQ to XYZ, and Block still trades on the NYSE.

Cover: Marchand du Panier, Jean-Eugène-Auguste Atget. Art Institute of Chicago, public domain. Chosen for a street seller with his basket (small merchants).