Slack Sues Microsoft in UK Over Teams Bundling Accusations

Salesforce and its messaging platform, Slack, have officially filed a lawsuit against Microsoft in London's High Court, alleging that the tech giant is using its market dominance to crush competition in the workplace software industry, a report has said.

Filed last week, the lawsuit accuses Microsoft of anti-competitive behaviour. Specifically, Slack argues that Microsoft "tied" and "bundled" its Teams messaging app with its Office suite, effectively forcing the product onto customers and limiting their ability to choose rival services.

According to a report by news agency Reuters, a Slack spokesperson said "Microsoft's practices harmed competition, ⁠using tying and bundling of Teams to limit customer choice".

This isn't the first time Microsoft's "bundling" strategy has come under fire. In 2020, Slack filed a similar complaint with the European Commission. To avoid a massive fine in Europe last year, Microsoft agreed to lower the price of Office products for customers who chose to opt out of Teams. However, the new UK lawsuit suggests that rivals don't believe those concessions went far enough.

While Microsoft fights in London courts, it has also faced the legal situation back in the US as the Federal Trade Commission (FTC) is reportedly accelerating a probe into whether Microsoft illegally monopolizes the enterprise computing market.

In February this year, a report said that FTC's investigation is focusing on whether Microsoft makes it harder for customers to use Windows or Office on rival clouds like Amazon or Google, and is the company unfairly integrating its Copilot AI and security software into Windows to lock out competitors.

Meanwhile, Google described Microsoft's practices as "problematic," filing its own complaint in Europe in late 2024. Google argued that Microsoft was using its "dominant" Windows Server software to trap customers inside its Azure cloud platform. While Google recently withdrew that specific complaint to allow EU regulators to conduct a broader investigation, the company remains a vocal critic.

Microsoft has defended its business model, arguing that some products aren't fully compatible with rival clouds because the underlying technology is simply different.