Interest accrual

Interest is the price of time, so only two things are allowed to move it: the clock and the contract. Accrual starts at activation—the posted value date of the disbursement, not the moment someone clicked “fund”—and runs under calculation settings resolved from the product at origination and frozen on the loan. A rate or day-count change made for next quarter’s applications would otherwise reach back and quietly re-price a loan somebody signed last year.

Pinned so preview and servicing agree

The product’s native block fixes the choices that must not drift between the schedule a borrower was shown and the one they are serviced on: the interest rate per period and its frequency, the declining-balance interest type, the interest-calculation period, equal-installment amortization, and a progressive schedule. Day-count conventions—the days-in-month and days-in-year treatment used to turn a rate into a period’s interest—are product configuration in the same block, and the finalized APR disclosure retains the unit-period, day-count, and fractional-period conventions it used.

For Harbor’s regular-period illustration—$8,400.00 at 13.25% with monthly installments:

opening principal        $8,400.00
annual rate                 13.25%
$8,400.00 × 13.25% ÷ 12     $92.75

Progressive schedules recalculate after dated transactions and schedule modifications while preserving posted history, so the accrued position always follows the actual balance path rather than the original projection.

Accrual is recognition, not money movement

An interest accrual recognizes interest receivable and income under the product’s accounting policy, written as balanced, value-dated journal entries with their source transaction attached. Cash arrives separately: a posted payment clears cash and reduces components in allocation order—Harbor’s first $517.14 payment allocates $92.75 to interest and $424.39 to principal. The accounting guide traces both event families entry by entry.

Backdating is controlled: a value-dated posting reprocesses dependent allocation and accrual deterministically and creates explicit adjustment entries—posted lines are never edited.

Ask again rather than adding a per diem

GET /v1/loans/{loanId}?associations=repaymentSchedule,transactions shows interest accrued, paid, waived, and outstanding; the loan summary’s payoff block projects interestAccruedToDate through the good-through date under the contract’s calculation settings, business calendar, and rounding policy.

A pause stops interest and nothing else

An interest pause is an effective-dated interval on the loan: eligible days inside it do not accrue contractual interest, while principal, payments, and prior accrual history are preserved. Any avoided-interest figure estimated before the interval ends is a projection—quoting it as final is how a borrower is promised relief the balance path does not deliver—and the amount is derived from the actual path once the interval completes. Fees, penalties, autopay, statements, and delinquency all continue; each needs its own explicit control.

Forgiving interest is a transaction, not an edit

Both waivers are governed commands with their own ledger effect:

• Waive accrued interest (waiveinterest) forgives a defined amount of eligible accrued, outstanding interest. Interest that has not accrued yet is out of scope, because forgiving it would be a rate change wearing a waiver’s clothes—and it would never appear as one in the loan’s history.
• Waive an interest payment (interestPaymentWaiver) targets the interest component of one scheduled obligation while preserving the installment and its principal.

Both post non-cash transactions with component allocation: accounting debits the configured interest-waiver or concession account and credits interest receivable or income according to the product’s accounting method. Human calls carry the case header when case management is enabled, maker-checker can park the command for a second approver, and every execution writes a governance record. There is no undo command: an erroneous waiver is corrected by a new governed action agreed in the case, so a borrower who was told their interest had been forgiven can always see when it was and on whose authority it changed.