Microsoft is investing in a hot startup that’s trying to weaken Google’s hold over Android.

People familiar with the matter say Microsoft is putting money into Cyanogen, which is building a version of the Android mobile-operating system outside of Google's auspices.

Microsoft would be a minority investor in a roughly $70 million round of equity financing that values Cyanogen in the high hundreds of millions, one of the people said. The person said the financing round could grow with other strategic investors that have expressed interest in Cyanogen because they’re also eager to diminish Google’s control over Android. The identity of the other potential investors couldn’t be learned.

Spokespeople for Microsoft and Cyanogen declined to comment.