Is "Cost savings" a singular term or plural terms?
The word savings, like clothes or thanks, is a plural and must take a plural verb:
His clothes are all over the bedroom floor.
His savings are in a Swiss bank account.
I'm not overly familiar with the context and usage of the term cost savings, but I assume it conforms to this convention.
Cost savings for this quarter are the largest we've had for years.
Contrast this with other nouns which may appear to be plural but are in fact singular, such as athletics or mathematics:
Mathematics is my favourite subject.