Interest Accrual, Billing, Penalty Interest, and Compound Interest

Chinese source: 计息、结息、罚息与复利 Locale: en-US Audience: Internal learning

Concept

Loan income mainly comes from interest. Loan interest processing covers regular interest, penalty interest after delinquency, compound interest on unpaid interest where allowed, and changes caused by prepayment, extension, or rate reset.

Regular interest = interest charged under the loan agreement
Penalty interest = additional interest after delinquency or default
Compound interest = interest on unpaid interest, subject to policy and regulation

Regular Interest Accrual

Element	Meaning
Principal balance	Base amount for interest calculation.
Rate	Fixed, floating, or tiered rate.
Start date	Date from which interest begins.
Day-count basis	Actual days, 360-day basis, 365-day basis, etc.
Billing cycle	Monthly, quarterly, maturity, or custom cycle.

Billing and Receivables

Billing or interest posting turns calculated interest into receivable or accounting recognition. The customer may not have paid yet, but the system has created interest due.

Distinguish:

• Accrual: calculating interest.
• Billing/posting: recognizing interest as due or receivable.
• Collection: customer actually pays interest.
• Interest reversal/adjustment: correcting interest.

Penalty Interest and Compound Interest

Type	Base	Trigger
Penalty interest	Past-due principal or defaulted amount.	Principal delinquency or contract default.
Compound interest	Unpaid interest.	Interest past due and policy allows compounding.

Compound interest treatment can be limited by policy or regulation. Do not assume it is always allowed.

Rate Changes

Rates can change because of:

• Floating-rate repricing.
• Customer risk grade changes.
• Extension or restructuring.
• Penalty rate after delinquency.
• Promotional rate expiration.

The system should keep rate-change history for recalculation, audit, and customer disputes.

Risks

Risk	Explanation
Day-count basis is wrong.	Interest is wrong across all periods.
Start or maturity date is wrong.	First and last period interest are wrong.
Penalty rules do not activate after delinquency.	Penalty income is understated and risk is mispriced.
Rate-change history is missing.	Customer statements and receivable changes are hard to explain.
Billing and collection are confused.	Income recognition and cash collection are misunderstood.

Related Topics

Topic	Use
Loan Products and Repayment Methods	Understand where rate rules come from.
Repayment Schedules and Installment Breakdown	Understand how interest enters installments.
Delinquency, Collections, and Loan Status	Understand penalty triggers.