Zoom will use its surging stock to pay for the deal, giving Five9 investors 0.5533 shares of its Class A common stock under an agreement announced Sunday. The target firm will become an operating unit of Zoom’s after the deal, which is subject to shareholder approval and slated to close in the first half of 2022.

The acquisition could propel Zoom into a $24 billion market for contact centers, the company said, helping it better compete with the likes of RingCentral Inc. that hook up users around the world via the internet. The deal is designed to help it build up Zoom Phone, a cloud-based calling service, the companies said in a statement. Five9’s customers include big names like Under Armour, Citrix, Athena Health and Lululemon, according to its website, and the transaction is also designed as a way for Zoom and Five9 to sell products to each others’ customers.

“We are continuously looking for ways to enhance our platform, and the addition of Five9 is a natural fit,” Zoom Chief Executive Officer Eric Yuan said in a statement.

Zoom rose to prominence after the pandemic hit in early 2020, becoming ubiquitous as people forced home by lockdowns used the service to connect remotely to work, school, friends and family. But investors have raised concerns this year about whether that growth will continue as vaccinations increase and shutdowns end.

As pandemic lockdowns have waned, the future of remote work has become a pressing question, and Zoom’s competitors have launched hybrid work features in a race to accommodate companies’ needs. Microsoft Corp. unveiled design changes to its Teams platform in order to improve remote workers’ interactions in meetings. Alphabet Inc.’s Google has revealed updates to its Workspace productivity suite, including new tools for its Meet videoconferencing system.

Goldman Sachs advised Zoom and Qatalyst Partners advised Five9. Rowan Trollope, CEO of Five9, will become president of Zoom while continuing to run Five9 as an operating unit.

Zoom is taking advantage of a stunning stock rally to bankroll the acquisition of Five9. Its stock soared about five-fold during 2020 and has risen another 7.3% in the year to date, pushing its market value past $100 billion.

The acquisition, according to data compiled by Bloomberg, is the fourth deal by Zoom since the start of the pandemic. In June, Zoom announced without disclosing terms that it had signed a deal to acquire German startup Karlsruhe Information Technology Solutions-kites GmbH, a translation software maker.

In March, Zoom was part of a group that acquired a minority stake in software firm Assembled Inc., the data showed. And in May 2020, it bought Keybase Financial Group Inc., which makes a secure messaging and file-sharing service, for undisclosed terms to bolster its encryption technology.