Slack Raises $250 Million; Tops $5 Billion ValuationSeptember 17, 2017 by quixnet Slack Raises $250 Million; Tops $5 Billion ValuationFortuneMessaging platform Slack valued at $5.1 BILLION in record breaking new funding roundDaily MailSlack Valued at $5.1B After SoftBank-led RoundInvestopediaSlack valued at $5bn after SoftBank joins fundraisingFinancial TimesFull coverage