What happened

Shares of Slack (NYSE:WORK) tumbled on Thursday, falling about 15% as of 10 a.m. EDT. The stock's decline followed Slack's inaugural quarterly earnings report, which was released after market close on Wednesday.

Shares of the workplace chat app are likely trading lower due to the company's outlook for its fiscal third-quarter loss per share. Management forecast a wider loss than analysts were expecting.

A chalkboard sketch of a chart showing a stock price moving lower.

Image source: Getty Images.

So what

For its second quarter of fiscal 2020, Slack's revenue rose 58% year over year to $145 million, coming in ahead of analysts' average forecast for revenue of $140.7 million. The tech company's non-GAAP (adjusted) loss per share for the period was $0.14 -- narrower than a consensus analyst estimate for a loss of $0.18.

In the company's second-quarter earnings release, Slack CFO Allen Shim said, "We remain focused on expansion within existing customers and growing our large enterprise customer base, and ended the quarter with 720 Paid Customers greater than $100,000 in annual recurring revenue, which is up 75% year-over-year."

Slack's total paid customers increased 37% year over year to more than 100,000.

Now what

For its fiscal third quarter, management expects revenue to be between $154 million and $156 million. While this guidance range is above analysts' forecast for fiscal third-quarter revenue of $153.2 million, it does imply a meaningful deceleration from the 58% revenue growth Slack reported in fiscal Q2.

The company guided for a fiscal third-quarter non-GAAP loss per share between $0.09 and $0.08 -- wider than the $0.07 loss per share analysts were expecting.