Microsoft has offered to charge different prices for its Office product with and without its Teams app to stave off a possible EU antitrust investigation and fine, two people familiar with the matter said.

Microsoft has been seeking to address the EU competition enforcer’s concerns since last year after Salesforce-owned workspace messaging app Slack complained to the European Commission, other people familiar with the matter told Reuters in December.

Slack in 2020 alleged that Microsoft has unfairly integrated its workplace chat and video app Teams into its Office product. The US tech giant introduced Teams in 2017 targeting the fast-growing and lucrative workplace collaboration market.

The European Commission on Thursday said there were other complainants besides Slack.

“We have received several complaints regarding Microsoft, including by Slack, regarding Microsoft’s conduct in relation to its Teams product. As you know the assessment is ongoing so we cannot comment further,” a spokesperson said.

Microsoft said it continued to engage cooperatively with the Commission and was “open to pragmatic solutions that address its concerns and serve customers well”.

Salesforce declined to comment.The EU antitrust watchdog is seeking feedback from Microsoft rivals on its proposal, the people said.

In the last decade, the European Commission fined Microsoft 2.2 billion euros ($2.4 billion) for practices in breach of EU competition rules, including tying or bundling two or more products together.

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