By kentoh @ Shutterstock.com

Slack invented the chat-based communications application category that has become a necessity in today’s work-from-home environment, but being the first to market doesn’t guarantee long-term success.

Microsoft Teams is also a chat-based communications platform, and it is included in Microsoft’s Office 365 subscription service. If you get Teams free, why buy Slack? Slack apparently feels Microsoft is engaging in anti-competitive behavior by giving away Teams with Office, but it’s a weak argument that Slack should lose.

For investors in Zoom, DocuSign, and other nice software products, the Slack/Teams dynamic should be a wakeup call. First mover advantage doesn’t always last.

The FT has more on Slack’s antitrust compliant with the EU.

The workplace messaging app Slack has filed a formal antitrust complaint against Microsoft with the EU, accusing it of unfairly bundling its rival app Teams with its Office 365 tools.

The complaint accuses Microsoft of “illegal and anti-competitive practice” of abusing its market power to eliminate rivals in alleged breach of EU competition law.

“Microsoft has illegally tied its Teams product into its market-dominant Office productivity suite, force installing it for millions, blocking its removal, and hiding the true cost to enterprise customers,” Slack said in a statement.

Slack has long chafed at Microsoft for essentially giving away Teams to Office 365 users, who are then less likely to pay extra for additional chat or video conferencing software.

But the formal antitrust complaint comes as the move to working from home raises the stakes.

Since the start of the year, Slack’s share price has risen by more than 40 per cent but the company has struggled to accelerate its revenue growth.

Meanwhile Microsoft Teams saw its users jump from 44m to 75m between March and April.

Read more here.