When an invoice goes quiet, the natural assumption is that someone decided not to pay it. Far more often nobody decided anything: it is sitting in a queue, waiting for a step that has nothing to do with willingness to pay.
Accounts payable exists to stop organisations paying for things they did not order, did not receive, or already paid for. The controls that achieve this are also what slows your invoice down. Understanding them turns chasing from a guessing game into a targeted question.
What happens after you hit send
In a mid-sized or large organisation an invoice passes through several hands before money moves, and none of the early steps involve anyone deciding whether your work was good.
It arrives at an intake point — a dedicated inbox, a portal, or increasingly an e-invoicing channel. It is captured and coded, meaning the data is extracted and assigned to a general ledger account, a cost centre and often a project. It is matched against the purchase order and any receipt evidence. It is routed to whoever holds authority for that amount. Once approved it joins a payment run, and the run executes on its own schedule.
The person who commissioned your work may appear at only one of those steps, or at none. This is why "I spoke to my contact and they said it is fine" often does not move anything: their approval may not be the approval the system is waiting for.
Matching and authorisation limits
Two controls account for most delays that are not simply queue time.
Matching compares the invoice to the purchase order and, for goods, the receipt record. Where all three agree the invoice can often be approved automatically. Where they disagree — quantity, price, a missing purchase order reference — it becomes an exception, and exceptions go to a human who has to work out what happened. This produces silence rather than a rejection notice, which is why the absence of news is not good news.
Authorisation limits mean different amounts need different approvers. A £500 invoice may clear with a line manager; a £50,000 invoice may need a director or a finance committee that meets fortnightly. Two invoices sent the same day can therefore be paid weeks apart purely because of who has to sign them.
A practical consequence worth knowing: splitting a large invoice into smaller ones to duck an authorisation threshold is a recognised pattern that controls are specifically designed to detect. It reads as circumvention rather than convenience.
The payment run
Most organisations do not pay invoices individually as they are approved. They batch payments into runs on a fixed cycle — weekly, fortnightly or monthly — and everything approved before the cut-off goes in the next one.
This single fact explains a great deal of apparently arbitrary payment timing. An invoice approved the day after a run waits for the following cycle regardless of its due date. On a monthly run, missing the cut-off by one day can mean waiting four more weeks.
It is worth asking a significant client two questions early: when is the payment run, and what is the approval cut-off before it. Knowing both lets you time your invoicing so that work finished at month end does not routinely miss the cycle by a day. Adjusting when you invoice is usually cheaper than shortening your terms.
Getting through the process faster
Almost everything that helps is done before the invoice is sent, not after.
Ask for the purchase order number before starting work, and put it on the invoice. This is the single highest-return habit for anyone invoicing larger organisations, because without it the invoice cannot be matched and immediately becomes manual work. Send to the intake channel rather than a personal inbox, and confirm what that channel is rather than assuming.
Then make the invoice easy to process. Match your line descriptions to the purchase order lines rather than restructuring them, invoice what was actually delivered, and include a named contact for queries so an exception can be resolved with one email instead of a search for who to ask.
When following up, ask stage-specific questions. "Has this been received and coded?" and "has it passed matching?" and "who is it with for approval?" each produce an actionable answer. A generic reminder produces a generic reassurance and no movement.
- Get the purchase order number before the work starts, and quote it on the invoice
- Send to the intake address or portal, not to your day-to-day contact
- Mirror the purchase order’s line structure and descriptions
- Bill what was delivered, not what was ordered, when they differ
- Name a contact for queries so exceptions can be resolved quickly
- Learn the payment run schedule and its approval cut-off
Common Mistakes
Sending invoices to your day-to-day contact
Your contact is rarely accounts payable. An invoice in a personal inbox may never enter the system at all, and when that person is away it simply waits.
Omitting the purchase order number
Without it the invoice cannot be matched automatically and becomes manual work for someone with no particular urgency. Ask for it before starting, not at invoicing time.
Reading silence as approval
Matching exceptions generate queue entries, not rejection emails. An invoice that has gone quiet is more likely stuck than being considered.
Splitting invoices to stay under an approval threshold
Controls are designed to detect exactly this pattern. It reads as circumvention, invites scrutiny, and can damage a client relationship more than a slow approval would.
Frequently Asked Questions
Why do large companies take so long to pay?
Rarely reluctance. The invoice passes through intake, coding, matching, an approver with the right authority, and then waits for the next payment run. Each step is a queue, and a monthly run can add weeks on its own.
What is a purchase order number and why do they keep asking for it?
It is the reference for the buyer’s pre-approved commitment to spend. Their system matches your invoice against it, so without the number there is nothing to match to and your invoice becomes an exception requiring manual handling.
Can I ask a client about their approval process?
Yes, and it is worth doing at the start of a relationship rather than during a chase. Where do invoices go, who approves at my typical amount, when is the payment run, and what is the cut-off — four questions that save months of guessing.
My contact approved it, so why has it not been paid?
Their approval may not be the one the system needs. Approval authority is tied to amounts, and the invoice may still need matching, coding or a higher signature before it reaches a payment run.
Sources & Further Reading
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