Microsoft has offered concessions to European Union antitrust regulators over its $26 billion bid for social network LinkedIn, the European Commission said on Wednesday, as the U.S. software company seeks to allay concerns over its largest-ever deal. The LinkedIn acquisition would allow Microsoft to add a suite of sales, marketing and recruiting services to its core business products as it gears up for next-generation computing. The commission will rule on the deal by Dec. 6 and is expected to seek feedback from rivals and customers before deciding whether to accept the concessions, demand more information or open a full investigation. The move came after the EU competition enforcement agency expressed concerns about the deal at a meeting with Microsoft executives last week. U.S. rival Salesforce, which lost out on the bidding for LinkedIn, has warned of the threat to innovation and competition, and urged regulators to examine the antitrust and data privacy issues thoroughly before clearing the deal. Microsoft, however, sees competition from social network Facebook and wants regulators to take that into account.