Salesforce has urged European Union regulators to investigate antitrust concerns relating to Microsoft's $26.2bn acquisition of professional social network LinkedIn.
Microsoft had hoped to get EU approval in the next few weeks for the company's largest purchase and one of the biggest technology acquisitions ever.
Salesforce, which is led by former Oracle executive Marc Benioff, also put in a bid for LinkedIn, and has claimed that Microsoft's ownership would give the firm an unfair advantage over the competition.
"By gaining ownership of LinkedIn's unique dataset of over 450 million professionals in more than 200 countries, Microsoft will be able to deny competitors access to that data, and in doing so obtain an unfair competitive advantage," said Burke Norton, Salesforce's chief legal officer.
"Salesforce believes this raises significant antitrust and data privacy issues that need to be fully scrutinised by competition and data privacy authorities in the US and the EU."
Microsoft said in response that the deal has already been cleared in the US, Canada and Brazil, and that Salesforce remains the biggest player in the CRM market.
"We're committed to continuing to bring price competition to a CRM market in which Salesforce is the dominant participant, charging customers higher prices today," said Brad Smith, Microsoft's president and chief legal officer.
The two companies have gone head to head for years with their CRM offerings and believe that combining their current datasets with LinkedIn's would give them an edge in the market.
There are various ways in which Microsoft could use LinkedIn's data. Integrating it with Office 365 and Dynamics could create a cloud service for firms that use all three tools.
People could quickly share contacts on LinkedIn for particular tasks, while jobseekers could update their CV on Word and LinkedIn simultaneously.
Integrating LinkedIn's Social graph with Microsoft's sales teams could help them better target customers with an Office 365 subscription, for example.
Perhaps most useful could be a workflow-type application in which LinkedIn could be used as a directory to source people to help with a certain document or PowerPoint presentation.
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