Why Messaging Startup Slack Keeps Raising Money It Doesn’t Need - Bloomberg Business

Also see Here's Why Stewart Butterfield Thinks Slack's Success Is a 'Historical Accident' (Fortune)

"Slack competes with other high-flying startups and major tech companies like Google Inc. and Facebook Inc. when trying to lure top talent. When job candidates ask why they should place their bets on Slack's stock instead of Google's, a soaring valuation helps answer the question. "Getting a valuation tick would be the only rationale for raising money," Butterfield said. "The reality is that over the last two years, compensation has gone crazy—especially in the last six months."
After an investment valuing the company at $2.8 billion less than a year ago, Slack is looking to increase that to as much as $4 billion with the current fundraising round. It's an unusual case in a cooling startup fundraising environment. Most companies can no longer treat venture capitalists like ATMs. Butterfield said raising money is generally harder now. Investors are skittish about an imminent plunge in the public markets, which could drag down the private markets, he said."

Why Messaging Startup Slack Keeps Raising Money It Doesn’t Need - Bloomberg Business