Microsoft has failed to head off a full-fledged EU investigation into Teams, with the bloc announcing it will investigate the company’s “anticompetitive practices.”

Microsoft has been under fire in the EU over Teams ever since Slack filed a complaint in July 2023. Slack maintained that Microsoft’s practice of bundling Teams with Office gave it an unfair advantage in the market.

The EU has been looking at how Microsoft bundles Teams but had stopped short of a full-fledged antitrust investigation. Microsoft, in turn, has signaled a willingness to make concessions, including decoupling Teams from Office and even being willing to charge for Teams.

Despite these concessions, it appears the EU is not satisfied and is opening a full investigation into Microsoft’s practices with Teams. The EU Commission outlined its concerns in a press release:

Microsoft includes Teams in its well-entrenched cloud-based productivity suites for business customers Office 365 and Microsoft 365. The Commission is concerned that Microsoft may be abusing and defending its market position in productivity software by restricting competition in the European Economic Area (‘EEA’) for communication and collaboration products.

In particular, the Commission is concerned that Microsoft may grant Teams a distribution advantage by not giving customers the choice on whether or not to include access to that product when they subscribe to their productivity suites and may have limited the interoperability between its productivity suites and competing offerings.

These practices may constitute anti-competitive tying or bundling and prevent suppliers of other communication and collaboration tools from competing, to the detriment of customers in the European Economic Area (‘EEA’).

“Remote communication and collaboration tools like Teams have become indispensable for many businesses in Europe,” said Margrethe Vestager, Executive Vice-President in charge of competition policy. “We must therefore ensure that the markets for these products remain competitive, and companies are free to choose the products that best meet their needs. This is why we are investigating whether Microsoft’s tying of its productivity suites with Teams may be in breach of EU competition rules.”