The watchdog is expected to make a preliminary decision on the $69 billion deal before the end of the month, according to a Verge source said to be familiar with the matter.
This will be followed by a final decision, which is due to be issued by October 18.
The CMA remains the last major roadblock to the deal closing. It initially blocked the acquisition in April due to concerns about its impact on the nascent cloud gaming market.
The US company then restructured its proposed acquisition of Activision Blizzard by agreeing to sell cloud streaming rights to Ubisoft, leading the CMA to launch a new merger inquiry.
“To address the concerns about the impact of the proposed acquisition on cloud game streaming raised by the UK Competition and Markets Authority, we are restructuring the transaction to acquire a narrower set of rights,” Microsoft president Brad Smith said in August.
“This includes executing an agreement effective at the closing of our merger that transfers the cloud streaming rights for all current and new Activision Blizzard PC and console games released over the next 15 years to Ubisoft Entertainment SA, a leading global game publisher. The rights will be in perpetuity.”