Microsoft's rumored "major restructuring" looks set to be unveiled by July 1st. All Things D reports that the reorg, which will focus on the devices and services vision, is being led by CEO Steve Ballmer without the consultation of all Microsoft's executives. The upcoming changes are said to be major, leaving some executives worried for their own positions and the plans for the company as a whole. All Things D quotes one insider as saying they're "titanic" changes, noting they might be attached to Ballmer's legacy at the company. "It’s the first time in a long time that it feels like that there will be some major shifts, including some departures," says the alleged insider.

Ballmer is reportedly considering a new structure that would create four separate divisions: enterprise business, hardware, applications and services, and an operating systems group. Bloomberg reported earlier this month that the OS group could be jointly led by Windows Phone chief Terry Myerson and head of Windows engineering Julie Larson-Green. Sources familiar with Microsoft's plans have revealed to The Verge that the new structure would see a significant focus on further aligning the Windows and Windows Phone operating systems. Microsoft moved to a shared Windows 8 kernel in October for Windows Phone, but applications that run on both platforms still need tweaking by developers, and the two Windows stores remain separate.

Microsoft is heading to San Francisco on Wednesday to host its annual Build developer conference. The software maker will unveil improvements to its Windows 8 OS in the form of a Windows 8.1 update that will enter public preview this week. Microsoft plans to finalize and ship the Windows 8.1 update in time for new 7- and 8-inch devices later this year. It's also expected to play a role in new Surface devices expected for the holidays. Any reorg news, internally at least, would likely come during the Build conference as Microsoft switches to its new financial year on July 1st.

If Ballmer's rumored reorg takes places then it will be the first company-wide structural change at Microsoft under Ballmer's leadership. The 57-year-old took over the CEO role from co-founder Bill Gates in January 2000, and made some significant changes in 2008 ahead of the company's Windows 7 software. Ballmer recently let former Windows chief Steven Sinofsky go, in an unexpected move just weeks after the company shipped Windows 8. It's clear a significant change is underway at Microsoft, and Ballmer has detailed a "fundamental shift" in Microsoft's business as it moves to a combination of hardware and software.