You get a 5% discount on the sixth and all subsequent subscriptions within each type of subscription:
Visual Studio Professional monthly
Visual Studio Professional annual
Visual Studio Enterprise monthly
Visual Studio Enterprise annual
For example, if you buy 6 Visual Studio Professional monthly subscriptions and 5 Visual Studio Enterprise monthly subscriptions, you'll pay the regular price on five Professional, get a 5% discount on the sixth Professional, and pay regular price on all five Enterprise subscriptions.
The discount only applies to charges in a given monthly billing period. So, if you buy five Visual Studio Professional annual subscriptions in one month, and then you buy five more the next month, you'll pay the regular price on all ten subscriptions. To receive the discount, all of the purchases need to occur in the same billing period.
Note
Microsoft no longer offers Visual Studio Professional Annual subscriptions and Visual Studio Enterprise Annual subscriptions in Cloud Subscriptions. There will be no change to existing customers experience and ability to renew, increase, decrease, or cancel their subscriptions. New customers are encouraged to go to https://visualstudio.microsoft.com/vs/pricing/ to explore different options to purchase Visual Studio.