Shares of work messaging platform Slack are expected to start trading on the New York Stock Exchange under the ticker "WORK."

The San Francisco company is set to start trading Thursday in what's known as a direct listing.

Unlike a traditional initial public listing, under a direct listing a company doesn't hire underwriters or sell new shares to raise money, it just lists existing shares. There is no offering price.

Slack co-founders Cal Henderson, left, and Stewart Butterfield pose for photos outside the New York Stock Exchange before their company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)

Slack co-founders Cal Henderson, left, and Stewart Butterfield pose for photos outside the New York Stock Exchange before their company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)

In a regulatory filing, Slack said the volume weighted average price of shares that changed hands in the private market from February through May was $26.38.

Slack aims to replace traditional work communication like email with its own messaging platform.

Other technology companies that made a splash by going public include Uber and video conferencing company Zoom Video Communications.

Slack CEO Stewart Butterfield poses for photos outside the New York Stock Exchange before his company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)

Slack CEO Stewart Butterfield poses for photos outside the New York Stock Exchange before his company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)

 Slack CEO Stewart Butterfield poses for photos outside the New York Stock Exchange before his company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)

Slack CEO Stewart Butterfield poses for photos outside the New York Stock Exchange before his company's IPO, Thursday, June 20, 2019. (AP PhotoRichard Drew)