Several department AWS accounts sit under one AWS Organizations payer, and leadership bought Reserved Instances in one account. What benefit awareness applies?

When several department AWS accounts sit under one AWS Organizations payer and leadership buys Reserved Instances in one account, consolidated billing awareness matters: unused Reserved Instance benefits can be shared across linked accounts in the organization, improving overall discount utilization for the municipality. That sharing helps parks compute in one account benefit from unused reservation capacity purchased under finance or the management structure, subject to matching rules—rather than stranding discounts in a single silo by default.

It is incorrect that RI discounts can never leave the purchasing account under any Organizations setup—consolidated billing enables sharing. It is false that only the management account may run EC2 or that member accounts cannot use RI benefits. Organizations does not automatically convert every RI into a Spot Fleet across all accounts. Those distractors invent account restrictions or magical conversions.

Exam caveat: Consolidated billing aggregates invoices and enables RI/Savings Plans benefit sharing across linked accounts. SCPs and OUs are separate governance features. Benefit sharing still requires matching usage attributes.

Operational check for the city org: enable Organizations with consolidated billing, review RI/SP coverage across accounts in Cost Explorer, place reservations where purchasing is centralized if desired, ensure member accounts still run their own workloads, and set tagging/showback so departments understand shared discount effects without fighting over whose budget "owns" the RI.