Dunning

Dunning is the methodical pursuit of money that a customer owes and has not paid on time. In its traditional sense it means sending a series of reminders of increasing firmness for an unpaid invoice. In subscription and online businesses the word has taken on a second meaning: the automated handling of a recurring payment that has failed, combining repeated attempts to charge the customer with messages asking them to update their payment details.

The word comes from the old English verb "dun", to demand payment of a debt persistently. Dunning sits between ordinary billing and formal debt collection. It is carried out by the creditor itself, or by its billing software, with the aim of recovering the payment while keeping the customer.

In business-to-business trade, goods and services are usually sold on credit, and the seller records the amount due in accounts receivable. When an invoice passes its due date, the seller's credit control function starts a dunning cycle. Accounting systems group overdue items by age and assign each customer a dunning level that rises as the debt gets older.

• Courtesy reminder. A polite notice shortly before or after the due date, on the assumption that the invoice was overlooked.
• Follow-up notices. Further letters or emails at set intervals, restating the amount and any late interest or fees the contract allows.
• Personal contact. A telephone call or account manager's message to find out whether there is a dispute, a missing document or a cash problem.
• Final demand. A formal notice that the account will be suspended or passed to a collection agency or lawyer.

In several European legal systems a formal reminder has legal weight, since it can be the step that puts the debtor in default and starts the running of statutory interest. Effective dunning shortens days sales outstanding and reduces write-offs.

Businesses that charge customers automatically through subscription billing face a different problem. The customer has agreed to pay and usually intends to, but the charge fails for a reason unrelated to that intent: the card has expired or been replaced, the account is temporarily short of funds, or the issuer's fraud system has refused the transaction. If nothing is done the subscription lapses, an outcome called involuntary churn, which for many subscription companies accounts for a significant share of all cancellations.

Automated dunning has two parts that run together. The first is the payment retry: the billing system attempts the charge again over the following days or weeks. The second is communication: emails, text messages and in-app notices tell the customer that payment failed and link to a page where they can enter a new card or choose another method. During this period the service may continue as normal, continue with a warning, or be restricted, depending on the merchant's policy. If all attempts fail, the subscription is paused or cancelled.

When and how often to retry determines how much revenue is recovered. The decline code returned by the issuer is the main guide. A soft decline such as insufficient funds may clear after the customer's next payday, so retries are spaced over days and timed for dates when balances tend to be higher. A hard decline for a closed or stolen card will never succeed, and the system should stop and ask the customer for new details. Providers increasingly use statistical models trained on large numbers of past attempts to choose retry times, an approach marketed as smart retries; the underlying retry logic must still respect network limits.

Card networks restrict reattempts. They cap how many times a declined transaction may be resubmitted within a period and charge fees for retrying after a refusal that signalled the card should not be tried again. Retries of recurring charges are sent as a merchant-initiated transaction, which in Europe places them outside the requirement for strong customer authentication provided the original mandate was properly authenticated. For bank debits the constraints are stricter: schemes limit how often a returned direct debit may be re-presented, and each failure may cost the payer a bank fee.

Much of the work happens before a charge fails. A card account updater service obtains new numbers and expiry dates from issuers when cards are reissued, and network tokenization keeps a stored credential valid across such changes. Merchants also send notices ahead of a card's expiry date and offer backup payment methods.

Dunning by a creditor for its own debts is lightly regulated compared with third-party collection, but it is not unregulated. Consumer protection law restricts misleading or harassing communications, and rules on electronic marketing and privacy govern the channels used. Once a debt is passed to an outside agency, specific collection laws apply, such as the Fair Debt Collection Practices Act in the United States. Charging late fees or interest requires a basis in the contract or in statute.

There is also a commercial limit. Aggressive retries can trigger bank fees for customers and complaints, and repeated messages may prompt a customer who had simply forgotten the subscription to cancel it. Businesses therefore measure dunning by the share of failed payments recovered and by what happens to those customers afterwards, not by recovery alone.