Slack IPO: stocks sell at 50% higher than expected as company's value tops $24bn

San Francisco-based company sold shares in direct listing, following Spotify's method, potentially ushering in new era of stock market sales

Workplace messaging service Slack became the latest hot technology company to sell its shares to the public on Thursday, soaring 50% higher than expected on its debut.

The San Francisco-based company's shares started trading on the New York stock exchange at $38.50 - well above the $26 guide price - and closed at $38.62 valuing the company at over $24bn, making a billionaire of co-founder Stewart Butterfield and potentially ushering in a new era of stock market sales.