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(Reuters) - Shares of Slack Technologies Inc surged 50 percent in their debut through a direct listing on Thursday, giving the workplace messaging app owner a valuation of about $23 billion.

The stock opened at $38.50, nearly 48% above a reference price of $26 set by the New York Stock Exchange on Wednesday.

Slack is the second high-profile technology company after Spotify Technology SA to opt for a direct listing over a traditional IPO.

The direct listing could further pave the way for companies looking to go public without the aid of Wall Street underwriters, who charge millions of dollars in fees.