From a legal perspective the idea of blocking companies from using open source code seems pretty interesting. It says 'subsidiary thereof', but aren't there fan

From a legal perspective the idea of blocking companies from using open source code seems pretty interesting. It says 'subsidiary thereof', but aren't there fancier relationships between related business entities that can be abused? Furthermore, is specifying 'Microsoft Corporation' even valid? MS operates all over the world and is registered all over the place. By specifying 'Microsoft Corporation' alone, what does this designate legally?