Slack shares recently traded at $32.31, down 5.5%. The stock has soared 90% over the past three months.
"While we continue to view Slack as a best-in-class team messaging offering that is favored by the technical community, we expect Microsoft Teams to continue to try and leverage its packaging within Office 365 to drive increased adoption, thus creating the potential for a more competitive environment," she wrote in commentary cited by MarketWatch.
That will diminish Slack's long-term growth rate, Bellini said. In addition, the company faces "elevated risk" of customer churn, in light of Slack’s "significant" exposure to small- and medium-sized businesses and its “exposure to industries directly impacted by the [coronavirus] pandemic."
Slack received mixed reviews from other analysts last week, after it reported stronger-than-expected first-quarter earnings, but withdrew its full-year guidance for “calculated billings.”
The results were good, “but not nearly enough,” Mizuho analyst Gregg Moskowitz wrote in a note to clients. He kept his neutral rating on the stock with a $29 one-year price target.
Wedbush analyst Dan Ives had a similarly cautious view, noting that while the company delivered solid first-quarter results, it will have “significant difficulty further penetrating the core enterprise market,” specifically Microsoft's Teams product.
Ives maintained his underperform rating but lifted his price target to $20 from $14.