The messaging company reported a third-quarter net loss of 2 cents per share on revenue of $168.73 million, a nearly 60% increase year over year. Analysts were expecting a loss of 8 cents per share on revenue of $156.02 million.
Fourth-quarter guidance was slightly off, however, with the company expecting to lose between 6 cents and 7 cents per share. Wall Street is expecting a loss of 6 cents per share.
Slack shares were down nearly 6% to $20.42 after hours Wednesday.
The company reported a 30% increase in paid customers to 105,000, with the number of paid customers with greater than $100,000 in annual recurring revenue rising 67% to 821. The number of paid customers with greater than $1 million in annual recurring revenue exceeded 50 for the first time in the quarter.
The stock dropped in November after Microsoft announced that its Teams messaging app has surpassed more than 20 million daily active users.
Microsoft said that the Teams app grew 54% since July following corporate partnerships with Alcoa and Telefonica S.A.
Last month, Slack reported 12 million daily active users in the second quarter, which was already behind the 13 million users Teams was reported to have in July.