“For Microsoft, Teams is increasingly where online work is done,” said Wayne Kurtzman, an analyst at IDC, a technology research firm. “It is becoming a platform for Microsoft.”
Slack is making its complaint as adoption of collaboration technology is surging. Slack, Microsoft Teams and Zoom are all experiencing huge demand because of the coronavirus-induced shutdowns that have forced much of the work force to toil from home.
In April, when the company reported its quarterly financial results, Microsoft said that Teams had 75 million daily users, more than double the number in early March. At the time, Satya Nadella, Microsoft’s chief executive, said, “We’ve seen two years’ worth of digital transformation in two months.”
Microsoft will report its results for the most recent quarter on Wednesday, after the close of stock trading. Despite the coronavirus-battered economy, Microsoft is expected to report revenue of $36.5 billion, up 8 percent, according analysts estimates compiled by IBES Refinitiv.
Slack, which was founded in 2014, has enjoyed rapid growth this year. Last month, reporting the results for its quarter ended in April, Slack said its revenue had jumped 50 percent to $202 million. It has more than 122,000 paying customers, typically companies with annual licenses, which was a 28 percent increase from the year-earlier quarter.
Mr. Schellhase, the Slack general counsel, said, “Microsoft is reverting to past behavior.”
But the illegal-tying claim, which Slack makes in its complaint, was not resolved in the federal browser case. Microsoft was found to have engaged in a range of illegal tactics to thwart competition, with contract restrictions and threats. An appeals court upheld those claims but sent the tying claim back to the lower court for reconsideration. The case, which was brought by the Clinton administration, was settled early in the Bush administration.