Slack Technologies Inc. has filed paperwork for its direct listing on the stock market, setting it up to be the second major company to use the nontraditional method for an initial public offering.

The workplace-messaging company’s IPO could come as soon as this spring, people familiar with the matter have said. By the time it debuts, Slack could be valued well above $7 billion, the level at which it recently raised money. Slack’s filing with the Securities and Exchange Commission was confidential and didn’t reveal any pricing information.

The company on Monday said it filed documents for a “proposed public listing,” indicating it could go public without raising money by selling shares to the public in what is known as a direct listing. The Wall Street Journal had reported Slack would use that approach to go public.

Direct listing is a maneuver pioneered by music streamer Spotify Technology SA last year. In a direct listing, the stock goes on a public market without the company raising any money for itself, unlike a typical IPO. The approach can save companies hefty underwriting fees associated with traditional offerings and avoid restrictions on when insiders can sell shares.

Direct listings are rare because companies either need to raise money or they don’t like the heightened risk that shares could flop in their market debut. In traditional IPOs, companies engage underwriters to line up investors ahead of time, help set an initial price and if necessary buttress the shares when they open for trading. With direct listings, the open market plays a greater role in setting the price.

Slack CEO Stewart Butterfield talks to The Wall Street Journal about the challenges of building a startup, the downsides of running a private company and his favorite computer game. Photo: Michael Bucher for The Wall Street Journal

Slack, which is based in San Francisco, runs an app used for group communication, especially in offices, and recently said it has more than 10 million daily active users in 150 countries. Workers use Slack to chat digitally with colleagues, sharing documents, web links, details of projects and more.


Like many technology companies, Slack will go public with a dual-class share structure that will give its co-founder and CEO, Stewart Butterfield, and others voting control in excess of their ownership stake, according to people familiar with the offering.

Slack is working with Goldman Sachs Group Inc., Morgan Stanley and Allen & Co. on its deal. The trio were the advisers on Spotify’s direct listing.

Spotify executed its direct listing with nary a hiccup in April 2018, garnering publicity for the method in the process. That emboldened companies to explore the option, people familiar with the matter have said. Still, Spotify’s stock is about 6% below where it closed on the first day of trading.

Many market observers expect 2019 to be a huge year for IPOs—despite a bumpy start. The U.S. government shutdown interrupted the exchange of documents between the SEC and companies pursuing a public listing. Slack’s filing shows the conduit has reopened, though the threat of another shutdown looms.


In addition to Slack, other companies that could begin trading publicly this year include Uber Technologies Inc. and Lyft Inc.—both of which have made confidential filings—and potentially Airbnb Inc. and Palantir Technologies Inc.

Slack has raised more than $1 billion since the app launched in 2013 at increasingly higher valuations and still has significant cash on its balance sheet, people familiar with the company said. In August, Slack raised $427 million in a funding round led by Dragoneer Investment Group and General Atlantic valuing the company at $7.1 billion. That came after it raised money from SoftBank Group Corp. in 2017.

The company emerged from a failed videogame effort initiated by Mr. Butterfield. The game didn’t catch on, but one of its features was developed into a messaging platform that became Slack.

Slack’s success caught the attention of several tech companies, including Microsoft Corp. , which launched a rival service called Teams nearly two years ago. The service resembles Slack, but it also leverages some of Microsoft’s widely used products, notably its Office software and Skype videoconferencing service.


Facebook, too, is trying to get a piece of the market with its Workplace service, which just added Nestlé SA as a customer. Alphabet Inc.’s Google also offers email and messaging services, and cloud-computing giant Amazon.com Inc. has a handful of collaboration services, including a videoconferencing service called Chime.

—Jay Greene contributed to this article

Write to Maureen Farrell at maureen.farrell@wsj.com