Slack Files EU Antitrust Complaint Against Microsoft

The workplace messaging platform Slack said Wednesday it has filed an antitrust complaint with the European Commission alleging that Microsoft is illegally tying its own product to its dominant Office software suite.

San Francisco-based Slack said the tech giant is abusing its market dominance and harming competition by promoting its own messaging service, Teams, as part of Microsoft Office.

The integration of Teams with Office hides its true cost to business customers, according to the complaint.

"Slack simply wants fair competition and a level playing field," said David Schellhase, general counsel at Slack.

Schellhase said the move is similar to Microsoft's efforts in the 1990s to tie its browser to the Windows operating system which led to a massive antitrust case.

"Microsoft is reverting to past behavior," he said.

"They created a weak, copycat product and tied it to their dominant Office product, force installing it and blocking its removal, a carbon copy of their illegal behavior during the 'browser wars.'

"Slack is asking the European Commission to take swift action to ensure Microsoft cannot continue to illegally leverage its power from one market to another by bundling or tying products."

Microsoft, responding to a request for comment, said its Teams service has grown because of its features, including video.

"We created Teams to combine the ability to collaborate with the ability to connect via video, because that's what people want," a Microsoft spokesperson said.

"With COVID-19, the market has embraced Teams in record numbers while Slack suffered from its absence of video-conferencing. We're committed to offering customers not only the best of new innovation, but a wide variety of choice in how they purchase and use the product."

Microsoft said it would provide information and answer any questions posed by the European Commission.

Under EU rules, a complaint from a private firm does not automatically trigger a regulatory investigation.