"I expect this to be a regular agenda item for board discussion for companies looking to go public," said Sarah Cannon of Index Ventures, which backed Slack. Airbnb Inc. is on track to be the largest tech company to embrace this new path. The home-rental company, valued by private investors at $35 billion, has said it intends to go public next year and is leaning toward a direct stock listing. One downside of direct listings is that they don't raise new funds for the companies involved. That's unnecessary for some startups that have already raised hundreds of millions of dollars in private markets. But other companies need the new money to fund growth, pay off debt or cash out early investors. Two of the highest-profile companies in Benchmark's portfolio, Uber Technologies Inc. and WeWork, chose traditional IPOs -- with dire results for some investors. Uber shares are down more than 30% from the May offering price, and WeWork pulled its plans recently.