Enterprise messaging service Slack is raising a $250 million round at a $5 billion valuation, TechCrunch has confirmed. We’re hearing that SoftBank, Accel Partners and other existing investors participated.

The $250 million financing amount was reported by Bloomberg. Axios first had the names of the lead investors. Recode originally reported on a $500 million round last month, but we’re hearing that was likely in reference to the same round and the amount just wound up being $250 million.

There have also been various reports about acquisition conversations, but at least one source with direct knowledge claims the parties never came close to finalizing a deal.

Yet investors certainly believe Slack has strong “exit” potential. Over $500 million in equity funding has been disclosed so far, and the $5 billion valuation means that some investors believe it will be acquired or go public at a value significantly higher than that.

We use Slack at TechCrunch for much of our internal communication. A lot of people love the instant messaging service for its modern interface. (And gifs! Some people are really excited about the Giphy integration.)

Slack has almost a cult following in Silicon Valley, but much of its success will be contingent on whether it is able to convince large enterprises around the world to switch services. Slack has touted itself as an alternative to email, but it’s not a platform for communicating with people outside your company.

Yammer once gained significant traction, but after it was acquired by Microsoft it became less trendy.