The US is entering a legal battle with Xbox-maker Microsoft to block its plan to purchase the gaming firm behind hit titles such as Call of Duty.
Regulators cited competition concerns, saying they feared that if the deal went through, Activision Blizzard’s games would stop being offered on non-Microsoft gaming consoles.
The Activision purchase was set to be the biggest in Microsoft history.
The company said it would fight to complete the $69bn (£56bn) deal.
Microsoft president Brad Smith said the company had “complete confidence in our case and welcome the opportunity to present our case in court”.
The complaint against Microsoft is among the most-high profile legal fights to emerge from US President Joe Biden’s pledge to take a harder line against monopolies.
The planned deal had already raised concerns in other countries, including the UK.
