Five9 is named for five nines, the 99.999 percent uptime that phone networks promise. The company spent its first eleven years selling call center software over the internet, back when most call centers still ran on racks of hardware bought from Avaya and Cisco. Agents logged in from a browser. Phone, chat and email arrived in one place. When Five9 went public in April 2014, cloud software for the front desk of customer service was still a young market.

Renting the Call Center

Five9 was incorporated in 2001 and is based in San Ramon, California, and when it went public it had engineering and support offices in Russia and Asia. Its bet was that companies would rather pay a monthly fee per agent than buy and maintain their own phone systems. Cloud delivery let a business add agents for a busy season, or seat them at home. It also let Five9 ship new features to every customer at once.

The Zoom Deal That Wasn't

Five9 priced at $7 a share in April 2014 and listed on Nasdaq as FIVN. The stock grew for years as call centers moved to the cloud. In July 2021 Zoom agreed to buy Five9 in an all-stock deal valued at about $14.7 billion. Zoom's shares fell, Five9 shareholders balked, and the two companies called it off that September. Five9 joined the S&P SmallCap 600 in August 2026 and remains public on Nasdaq.

Cover: Westminster Clock Tower, Félix Hilaire Buhot. Art Institute of Chicago, public domain. Chosen for a clock tower (five nines of uptime).