Stewart Butterfield, co-founder and chief executive officer of Slack Technologies Inc., speaks during an event in San Francisco, California.
David Paul Morris | Bloomberg | Getty Images
Slack shares fell as much as 20% in extended trading on Tuesday after the team communications software company reported fiscal second-quarter results and full-year guidance that exceeded analysts’ expectations. Although it beat on full-year guidance, revenue growth in the quarter, which ended on July 31, came in below 50% on an annualized basis, in line with the two previous quarters. That’s a disappointment compared with video-calling software company Zoom, which showed 355% growth during the coronavirus…