Microsoft’s proposed A$106.5 billion Activision buyout has faced a level of regulator scrutiny that the tech giant wasn’t expecting.

This is leading Activision insiders to privately wonder whether Microsoft might just pull the pin and pay the A$4.6 billion breakup fee rather than agree to strict proposed terms.

Currently, the deal is being reviewed by the various anticompetition bodies in the US, UK, and European Union.

The most obvious sign of unrest came last week, when Microsoft declined offering the EU “behavioural remedies”, such as agreeing formally to allow tentpole games such as Activision’s Call Of Duty to feature on competing consoles.

This is despite Microsoft gaming CEO Phil Spencer publicly saying the company will continue releasing Call of Duty on PlayStation, with plans to bring it to other consoles.

The EU probe starts today, and is expected to have stronger caveats for the sale than regulators in the UK and US.

“We’re very appreciative of our close working relationship with Microsoft,” a spokesperson for Activision said, denying any pre-deal jitters.

“We’re confident in the deal and its progress, and we know Microsoft is working diligently to get it done. Any suggestion to the contrary is false.”

Microsoft also denied the deal was in trouble.

“From the moment this acquisition was announced, we’ve worked urgently to show we’re serious about taking the steps needed to earn approval – including making proactive commitments about how we’ll run our business with gamers and developers at the centre,” a spokesperson said.

“The process has progressed as expected and will still anticipate the deal to close on schedule.”