Currently Online 
In recent weeks, Microsoft has accused Sony, its chief video game rival, of misleading regulators. Its lawyers have showed off game consoles, including an Xbox, to British officials. And the president of a major union that Microsoft wooed has spoken up on the company's behalf to the Federal Trade Commission.
Microsoft's aim is simple: persuade skeptical governments around the globe to approve the blockbuster takeover. Sixteen governments must bless the purchase, putting Microsoft under the most regulatory pressure it has faced since the antitrust battles of the 1990s. And in three key places — the United States, the European Union and Britain — regulators have begun deep reviews, with the European Commission declaring this month that it was opening an in-depth investigation of the deal.
"If this deal had happened four years ago, this would hardly be of any interest," Brad Smith, Microsoft's president, said in an interview. "If one cannot do something easy, then we'll all know you can't do something hard."
At the heart of regulators' concerns about the Activision deal is whether it violates antitrust laws by giving Microsoft outsize power in the video game industry. They worry that Microsoft could pull Activision's games away from competitors like Sony or use them to get an unfair leg up as more gaming is streamed online.
Mr. Smith said Microsoft was open to formally agreeing to place limits on its business practices to resolve antitrust concerns. But the United States and other countries increasingly see such promises as insufficient unless a company spins off part of its business.
In a statement, Jim Ryan, the chief executive of Sony Interactive Entertainment, said it was "not true" that his company had misled regulators. He said that Microsoft was "a tech giant with a long history of dominating industries" and that "it is highly likely that the choices gamers have today will disappear if this deal goes ahead."
Microsoft said that on Nov. 11 it offered Sony a 10-year deal to keep Call of Duty on PlayStation. Sony declined to comment on the offer.
Last month, Mr. Spencer and other Microsoft executives brought an Xbox, a PlayStation, a Nintendo Switch and other devices to a meeting with regulators in London, where they showed off Call of Duty and other games to illustrate a dynamic market, people familiar with the visit said.
- The offer has been increased to 10 years, Sony declined to comment, Lol. Ridiculous.
- Sony saying choices will disappear if the deal goes ahead, ironic.
In the United States, more than 10 staff members at the F.T.C. are reviewing the deal, a person with knowledge of the agency said. They interviewed executives, including Mr. Nadella and Mr. Smith, in the late summer and fall.
