Dunning
Dunning is the practice of sending structured, escalating payment reminders to customers with overdue invoices, moving from friendly nudges to formal demands as the balance gets further past due. A dunning sequence is a scheduled series of reminders that escalates in tone and channel as an invoice ages past its due date.
You have 340 overdue invoices in your AR system, and your team can personally contact 15 customers per day. Without automation, 325 of those invoices get no outreach this week. Dunning closes that gap, and the difference between a well-designed dunning sequence and a generic one shows up as days of DSO. Dunning is the automated process of sending sequential payment reminders to customers with overdue invoices. The term comes from 17th-century English financial practice, but the concept is basic to modern AR: when a payment is past due, the company sends a series of notices, starting with a polite reminder and escalating in urgency, to prompt payment without damaging the customer relationship. Dunning sequences are time-based. They trigger at set intervals after the invoice due date (day 3, day 10, day 20, day 30) and usually combine channels: mostly email, sometimes SMS or automated phone calls. The sequence ends when the invoice is paid, when the customer disputes the invoice and dunning pauses for resolution, or when the balance moves past the sequence into manual collections. Dunning is the automation layer that gives every overdue invoice systematic outreach regardless of team capacity. Without it, collections is limited by headcount. With it, your people focus on the exceptions (high-balance accounts, complex disputes, customers who don't respond to automated outreach) while the sequence handles the volume.
How dunning sequences work
A dunning sequence is defined by its timing, channels, message content, and escalation logic. Timing sets when each notice goes out relative to the invoice due date. A typical B2B sequence might send a gentle reminder at day 3, a more direct follow-up at day 10, a firm notice with a payment link at day 20, and a final notice at day 30 before escalating to manual collections. Spacing between notices should reflect realistic customer AP cycles. B2B customers usually run AP weekly or biweekly, so notices timed a day apart may not line up with when the customer is actually processing payments. Channel selection affects response rates. Email is the default, but for high-balance accounts or customers who have ignored email reminders, adding a direct call or a portal notification raises the contact rate. Some AR platforms support multi-channel sequences, such as email for the first two reminders and an automated phone call for the third. Message content matters as much as timing. Generic dunning messages ('Your invoice is overdue. Please remit payment.') get lower response rates than messages that include the specific invoice number, amount, due date, and a direct payment link. The easier it is for the customer to pay the moment they read the reminder, the higher the payment rate. Tone should escalate from friendly reminder to direct request to formal notice with consequence language. When the wording escalates at the same pace as the timing, the customer reads the balance as increasingly serious.
Where it gets complicated
Dunning sequences need to pause when a customer enters a dispute. An automated sequence that keeps sending payment demands during an open dispute frustrates the customer, tells them the company isn't listening, and can turn a resolvable billing disagreement into a relationship problem. Well-configured dunning systems have a dispute flag that pauses the sequence for that invoice until the dispute is resolved. The hard part is making sure the flag actually gets applied: when a customer calls to dispute an invoice, the AR team has to log it in the system instead of handling it outside the dunning workflow. Customer segmentation also affects how well dunning works. A single sequence applied to every customer ignores the fact that a Fortune 500 customer with complex AP processes behaves differently from a small business. Enterprise customers may legitimately need longer to move invoices through internal approvals; aggressive dunning at day 5 creates friction without speeding up payment. Sequences segmented by customer size, payment terms, or historical payment behavior produce better results than one-size-fits-all automation. Payment plans are a specific edge case. When a customer can't pay in full, a structured plan with defined installments may work better than continued dunning against the full balance. AR platforms that support payment plans (installment schedules tied to the original invoice, with dunning following the installment due dates instead of the original due date) give collections teams an option that a plain dunning sequence doesn't.
How platforms handle it
Almost every AR automation platform includes some form of dunning. The real differences are in how far you can customize it and how much logic it supports. Out-of-the-box templates give you a starting point: pre-written emails, default timing intervals, standard escalation paths. For companies with simple AR and a uniform customer base, standard templates may be enough. For companies with diverse customer segments, complex payment terms, or high dispute rates, you need customization. What to probe in a platform evaluation: Can you build multiple dunning sequences and assign them to customer segments, or is there one global sequence? Can the sequence be paused at the invoice level when a dispute is flagged, and does that pause happen automatically or need manual action? Can message content be personalized beyond invoice number and amount, pulling in the account manager's name, preferred payment method, or customer-specific payment portal links? Does the platform track dunning performance (open rates, payment rates by sequence step, average days-to-pay by sequence type) so you can tune the sequence based on what works? Can the sequence branch on customer behavior, for example creating a follow-up call task if an email went unopened for three days? These layers separate platforms that simply send dunning emails from those that have worked out what makes dunning collect cash.
Questions to ask
- Are dunning sequences segmented by customer type, payment terms, or balance size, or is there one sequence for all customers?
- Does the dunning sequence automatically pause when an invoice is flagged as disputed, or does it require manual intervention?
- What channels does the dunning sequence support beyond email, and can multi-channel steps be configured based on prior response?
- Does each dunning notice include a direct payment link tied to the specific invoice, or does it only reference the invoice number?
- How does the sequence handle partial payments? Does it update to dun for the remaining balance, or continue with the original amount?
- What reporting exists to measure dunning performance, such as payment rates by sequence step and average days-to-collect by segment?
Common mistakes
The most common dunning mistake is running every customer through the same sequence regardless of account size or relationship. A $300K enterprise customer getting the same automated email as a $2,000 small business customer is a relationship misstep; enterprise customers expect a person to contact them, not an automated notice. The sequence logic should route large-balance accounts to manual collections outreach sooner instead of running them through the full automated sequence. The second mistake is continuing to dun disputed invoices. When the AR system has no way to flag an invoice as disputed and pause the sequence, customers receive increasingly urgent automated demands while they are telling the AR team about a dispute by phone or email. The contradiction makes the company look disorganized and escalates disputes that one coordinated outreach could have resolved.
Dunning in collections
The word collides with two unrelated things in search results: the Dunning School of historiography, and SAP transaction codes. In receivables, dunning means the reminder process itself. The design decisions that matter are the escalation schedule, who the reminder goes to once an invoice passes a threshold, and when a human collector takes over from the automated sequence.
Comparing AR automation
AR tools separate on remittance handling, because a payment with no readable remittance advice becomes manual work no matching engine removes. Once dunning is settled as a requirement, read the AR Automation Software category guide for how the market splits, then weigh the HighRadius profile against the Versapay profile on that requirement rather than on the feature list. Our HighRadius pricing breakdown records what the vendor publishes and what is quote-based. The HighRadius against Versapay comparison sets two of them side by side on the same criteria. Before you book demos, put your own numbers through the AR automation cash flow calculator so the business case is written down before a vendor writes it for you.
Frequently asked questions
How is dunning different from collections management?
Dunning is the automated, time-based part of collections: a predefined sequence of payment reminders sent without manual intervention. Collections management is the broader process that dunning sits within. It includes manual outreach for high-priority or complex accounts, internal and external escalation paths, promise-to-pay tracking, dispute resolution, and ultimately the decision to write off a balance or refer it to external collections. Dunning is the automated baseline; collections management is the full system, with both automated and human-led parts.
How many dunning notices is too many before a customer relationship is damaged?
There's no universal number. It depends on the customer, the balance, and the tone. In practice, three to four notices over 30 days, with escalating urgency, is standard for B2B. Past that, more automated outreach without a human touchpoint usually works less well and frustrates the customer. For balances still open after three to four automated notices, the best next step is usually a direct call from the account manager or AR manager, which signals that the issue needs a conversation rather than another email.
Should dunning sequences be paused for customers who are good payers but occasionally run late?
Many AR platforms let you configure dunning sensitivity by customer tier or payment history. For long-standing customers with strong payment histories, it's reasonable to delay the first dunning trigger (starting at day 10 past due instead of day 3, for example) to avoid friction from automated notices on invoices that are only slightly late. This is a segmentation decision that balances collections discipline against the relationship. Build the logic into the system configuration instead of making ad hoc exceptions that create inconsistency.
Related terms
Accounts Receivable, AR Aging Report, and Bad Debt Write-Off come up in the same workflow as dunning, and the rest of the AR automation cluster is indexed in the finance operations glossary.