The decision "rejects a pragmatic path to address competition concerns and discourages technology innovation and investment in the UK,” said Microsoft.
The authority the deal would "would alter the future of the fast-growing cloud gaming market," leading to "less choice for UK gamers."
The Financial Times reports that the UK's Competition and Markets Authority is likely to approve the $69 billion acquisition.
The FTC specifically subpoenaed Nintendo of America's Steve Singer for up to seven hours of testimony regarding the deal.
PlayStation boss Jim Ryan believes that a degraded version of Call of Duty on PlayStation would cause irreparable harm to the company.
Both Sony and Microsoft have released statements in response to the UK CMA's softened stance on the Activision Blizzard acquisition.
Activision Blizzard CEO Bobby Kotick insists that the company's relationship with Sony won't be affected in spite of its efforts to block the Microsoft acquisition.
The Commission concluded its investigation, stating the merger "would not substantially restrict competition in certain business fields."
The UK's regulatory body has released a statement where it believes that the merger won't harm competition in the gaming console market.
The EU and Microsoft are more interested in potential problems in the cloud gaming market than the console market, going by the lack of Sony's name in statements.
Microsoft is arguing against Sony's claims of the importance of Call of Duty by pointing out that Sony can make its own competitor to the shooter franchise.
The EU regulatory body has announced that it is postponing its deadline to decide the fate of the $69 billion acquisition.
In the newest chapter of the investigation into Microsoft's acquisition of Activision Blizzard, Sony has released a response regarding its subscription service.
"Despite clearly intending to use these agreements in its defense, Microsoft has refused to produce underlying internal documents related to these agreements," the American agency says.
The company has so far signed binding 10-year agreements with the likes of Nintendo and Nvidia for future Call of Duty titles.
Sony remains staunch in its stance that Microsoft's Call of Duty deal for PlayStation will do more harm than good.
"Even if such degradations could be swiftly detected, any remedy would likely be too late, by which time the gaming community would have lost confidence in PlayStation," Sony says.
Activision Blizzard EVP/CCO Lulu Cheng Meservey reveals the SIE President and CEO said this on February 21st in Brussels.
Microsoft believes that, with some optimisation, Call of Duty: Modern Warfare 2 and Warzone 2.0 should run just fine on the Nintendo Switch.
According to Microsoft, despite its acquisition of Activision Blizzard, Game Pass prices will not be raised.
