Enterprise collaboration app maker Slack is raising $250 million in a new funding round led by SoftBank and venture firm Accel, which values the company at around $5 billion, according to media reports.
Slack will also let employees and other shareholders sell equity to investors as part of the deal.
Spokeswoman Julia Blystone declined to comment on funding rumours, Reuters said.
Last month it was reported Amazon was among several companies looking into acquiring Slack. At the time, a deal was expected to value the firm at at least $9 billion.
However, an acquisition is no longer on the cards, at least in the short term.
Slack has 5 million daily active users – 1.5 million of whom pay to use the service – and had $150 million in annual recurring revenue as of 31 January.
Other previous investors are also reportedly participating in the round. Slack has in the past raised money from venture firms incuding GGV Capital, Spark Capital and Thrive Capital.
SoftBank, which is also seeking a multibillion dollar stake in Uber, saw its technology investment fund raise more than $93 billion in May, making it the world’s largest private equity fund.