REFILE-Slack surges 50% in unusual listing, grabs $23 bln valuation <!-- no image --> <div>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.<div class="feedflare"> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=yhEnCtMjO-I:xzTGOCql8Ew:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?d=yIl2AUoC8zA" border="0"></a> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=yhEnCtMjO-I:xzTGOCql8Ew:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?i=yhEnCtMjO-I:xzTGOCql8Ew:V_sGLiPBpWU" border="0"></a> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=yhEnCtMjO-I:xzTGOCql8Ew:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?i=yhEnCtMjO-I:xzTGOCql8Ew:F7zBnMyn0Lo" border="0"></a> </div><img src="http://feeds.feedburner.com/~r/reuters/UKBankingFinancial/~4/yhEnCtMjO-I" height="1" width="1" alt=""></div> Posted by Reuters