FinOps & Cost Optimization for a Financial Institution

A financial institution was operating approximately US$20,000 per month in AWS, supporting applications across different investment business areas.

Despite the importance of cloud infrastructure to the business, costs were concentrated in a single bill, and there was no reliable way to identify how much each area consumed.

The project established a FinOps and Cost Optimization practice, aligning Technology and Finance to create transparency, accountability, and continuous optimization of cloud investment.

The infrastructure had grown in a decentralized way, following the individual needs of each business area.

As a result, Finance struggled to answer fundamental questions:

• How much is each area consuming in AWS?
• Which application is generating a given cost?
• How should shared costs be allocated across areas?
• Which areas are over budget?
• Where are the real opportunities for savings?

In addition to the allocation challenge, the lack of governance made waste difficult to identify and cloud financial planning unpredictable.

The initiative was structured around the Cost Optimization pillar of the AWS Well-Architected Framework.

The work was divided into four fronts:

• Visibility: map AWS consumption and identify the areas and applications responsible for costs.
• Allocation: create a cost distribution model for showback and chargeback across business areas.
• Control: establish budgets, alerts, and periodic consumption reviews.
• Optimization: identify waste, oversized resources, and cost-reduction opportunities.

A financial governance layer was created over the existing AWS environment.

Resources were classified by business area, application, environment, and cost center, turning the AWS bill into a business-oriented financial view.

Shared costs, including connectivity, common infrastructure, and corporate platforms, were allocated using defined criteria across the areas that benefited from them.

Implementation began by establishing a baseline for the approximately US$20,000 in monthly consumption.

Based on this assessment, resources were classified by area and application, and a cost allocation model was defined together with Finance.

Once visibility was established, budgets and alerts were implemented for each area, along with a recurring review cycle for the main cost drivers.

The opportunities identified became part of a continuous optimization backlog prioritized by financial impact.

• AWS Cost Explorer
• AWS Cost Categories
• Cost Allocation Tags
• AWS Budgets
• AWS Cost Anomaly Detection
• AWS Compute Optimizer
• Savings Plans
• Reserved Instances
• Terraform

The initiative changed how cloud costs were managed across the organization.

Instead of a single expense centralized under Technology, consumption became associated with the areas and applications that actually used the resources.

This allowed Finance to incorporate AWS into its budgeting and financial-control processes, while Technology teams began treating cost as part of architecture and operations decisions.

Each area gained a clearer understanding of how its applications directly affected the budget.

• US$20,000 per month in AWS consumption began to be tracked through a structured FinOps model.

• More than 95% of costs were attributed to business areas, applications, or financial categories defined by the organization.

• An 18% potential reduction in spend was identified through rightsizing, waste elimination, and optimization of purchasing models.

• Approximately US$43,000 in potential annual savings, based on the initial baseline of roughly US$240,000 per year in AWS expenditure.

• 100% of business areas gained consumption visibility, allowing Finance to allocate cloud spending across their respective budgets.

• FinOps became part of ongoing operations, with recurring reviews of budgets, anomalies, and optimization opportunities.