What happened

Salesforce (CRM -2.45%) shareholders were a cautiously optimistic lot on Monday, after news broke of a major competitor to their company possibly retreating from a simmering regulatory dispute. As a result, Salesforce stock closed the day 1.5% higher, more or less matching the S&P 500 index's gain.

So what

That competitor is the ever-powerful Microsoft (MSFT -3.58%), which has been a thorn in Salesforce's side because of its Teams application. This has drawn criticism for being very similar to Slack, the highly popular corporate messaging platform Salesforce acquired in mid-2021.

Monday morning, citing "people familiar with the matter," Reuters reported that Microsoft is attempting to allay regulatory concerns in Europe about a complaint lodged over Teams. Slack alleged in 2020 that the tech giant had unfairly integrated the app into its Office software productivity suite, filing a formal grievance on the matter with the E.U.'s executive arm, the European Commission.

In a press release issued at the time, Slack quoted its Vice President of Communications and Policy Jonathan Prince as saying that "Slack threatens Microsoft's hold on business email, the cornerstone of Office, which means Slack threatens Microsoft's lock on enterprise software."

Now what

According to the Reuters article's sources, Microsoft has made a preliminary offer of concessions in order to address the complaint -- and possibly to head off a potential investigation from the Commission. The story did not provide any details about this apparent set of concessions.

Neither Microsoft nor Salesforce has yet commented on the article.