The Alphabet, SoftBank and Comcast-backed communications platform developer is reportedly set to close a General Atlantic-led round at a $7bn valuation.

Slack, the US-based workplace communication platform backed by telecommunications group SoftBank, mass media group Comcast and internet technology conglomerate Alphabet, is raising about $400m in funding, TechCrunch reported yesterday.

Growth equity firm General Atlantic will lead the round, according to multiple sources, and could be joined by investment firm Dragoneer. It is set to value Slack at $7bn post-money, approximately $2bn more than its last round, closed in September 2017.

Slack has built a workplace communication platform that had accumulated…