Team messaging services provider Slack Technologies Inc. is raising a new round of about $400 million on a valuation of $7 billion, according to an unconfirmed report published Tuesday.

TechCrunch made the claim late Tuesday, saying that it has heard from “multiple sources” that a new investor, General Atlantic, is leading the round, with Dragoneer also said to be in the mix.

The round would be Slack’s largest to date. It last raised $250 million in a round led by SoftBank Group Corp.’s Vision Fund in last September on a valuation of $5 billion. Slack had been previously valued at $3.8 billion when it raised $200 million in April 2016 and $2.8 billion when it raised $160 million in April the year prior.

The new money would come into Slack as it faces its most serious competitor since it was founded in 2009: Microsoft Corp. and its Teams product that launched into general availability in March 2017.

Analysts were quick to predict that Microsoft Teams would surpass Slack within two years. Microsoft seriously upped its ante against Slack by launching a free version of Teams in July.

On every level, the free version of Microsoft Teams is either as good as or surpasses Slack’s free version, with additional memory, group calling and integrated, real-time content creation with Office Online apps, including built-in Word, Excel, PowerPoint and OneNote. Teams free also offers unlimited app integrations with 140-plus business apps to choose from, including Adobe, Evernote and Trello. By comparison, Slack only offers up to 10 apps and integrations.

Slack has tried to hit back such as through its acquisition of the Missions app in July. But its biggest play to date has been a deal with Atlassian Corp. Plc. to acquire Atlassian’s Hipchat and Stride platforms, with the two companies agreeing to work closely in the future.

Image: Slack