We are looking for a specialist who combines financial know-how with strong analytical skills to join our Core Ledger team. Our platform contain core ledger systems both fully developed internaly and developed and delivered by external suppliers. As an Interest & Product Logic Specialist, you will define and document the business rules behind interest, fees, and product configurations, and verify and test that what our internal- and external suppliers deliver matches our requirements and works correctly. A significant part of this role is providing hands-on internal support to colleagues across the business who have questions about interest, fees, and product behaviour — this is something all specialists in the team spend a lot of time on. Getting this right is essential — it directly affects how accurate and competitive our financial products are. You will join a small, close-knit team and have a great opportunity to make a direct impact early on and help shape it as it grows.
Key Responsibilities
Define and document detailed requirements for interest calculation logic, accrual rules,



and fee structures, to be delivered by external suppliers
Translate financial product requirements from business and product teams into precise specifications for our suppliers
Verify and test the product configuration delivered by suppliers, ensuring it behaves correctly for all financial instruments
Ensure the mathematical and financial correctness of calculation logic delivered, including edge cases and regulatory requirements
Collaborate with finance, compliance, and product teams to validate that supplier deliveries meet business intent
Support audit and regulatory reporting by ensuring calculation logic is transparent, traceable, and well-documented
Investigate and resolve discrepancies in interest calculations, fee postings, or product behaviour, working with suppliers when needed
Define and execute test cases for financial calculation logic, including boundary and regression t

📌 Product Specialist (España)
🏢 TF Bank
📍 España