European Union regulators Thursday opened an antitrust investigation into concerns that Microsoft's bundling of its Teams app with other Office products was giving it an unfair advantage.

Teams is the company's popular communication and collaborative tool used by thousands of businesses worldwide. The company includes Teams with other popular suites for businesses Office 365 and Microsoft 365.

The European Commission, the European Union's top competition enforcer, said bundling them may constitute anti-competitive behavior. It said it would carry out an investigation as "matter of priority."

"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," the European Commission said in a statement.

Teams indispensable for businesses

"Remote communication and collaboration tools like Teams have become indispensable for many businesses in Europe. We must therefore ensure that the markets for these products remain competitive," said Margrethe Vestager, the EU antitrust commissioner.

"This is why we are investigating whether Microsoft's tying of its productivity suites with Teams may be in breach of EU competition rules," she added.

Microsoft said in a statement that it respected "the European Commission's work on this case." It added that it would "continue to cooperate with the Commission and remain committed to finding solutions that will address its concerns."

Last week, the German alfaview video conferencing company added its own complaint over Microsoft Teams, arguing that bundling gives the US tech giant an unmatched competitive advantage.

In July 2020, popular workplace communication tool, Slack Technologies, submitted a complaint against Microsoft, alleging that Microsoft illegally tied Teams to its dominant productivity suites.

Microsoft cleared hurdles in the past

In May, the European Commission said they would allow Microsoft to buy the video game company Activision Blizzard in what would give control Microsoft control over popular franchises like "Call of Duty."

It would make Microsoft one of the biggest video game publishers in the world.

Microsoft also has won EU clearance to buy video game company Zenimax and speech recognition company Nuance.