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The Hidden Cash Problem / AR Edge Cases Nobody Planned For: W9s, POs and Portals

The hidden cash problem: Post 5 of 10

1.5 AR Edge Cases Nobody Planned For: W9s, POs and Portals

Short answer: The most common AR edge cases are missing PO numbers, W9 requests, out-of-office approvers, AP portal onboarding and approval bottlenecks. They are predictable, so they should be handled inside the AR workflow rather than in someone's inbox.

A contract gets signed and the invoice goes out on time, and then it stops moving. The customer is willing to pay, but their AP process needs something else first, usually a W9 or a PO number nobody captured at close. Sometimes it's a supplier registration that takes three weeks.

Finance usually handles these by hand, one at a time, even though the same exceptions come back every quarter. Edge cases are responsible for 39% of the slowdown in cash flow, based on Monk's proprietary customer data measured with its first 100 customers. Because nobody plans for them, they take the same hours every cycle.

What happens when an exception fires

Standard path: contract signed, invoice created and sent, payment received. Exception path: a missing PO, W9 or portal requirement triggers manual triage, back-and-forth and delays, followed by invoice resubmission and a restarted payment clock.

A reminder email does nothing for a customer whose AP team is waiting on a W9, and calling the account manager won't produce a missing PO. An AR tool should handle routine exceptions like these on its own and flag the ones that need a person.

The predictable exception types

Exception type What it holds up
Missing PO number AP auto-rejects on intake. Invoice restarts from zero.
W9 request Payment held until tax form is submitted and verified.
Out-of-office approver No escalation path. Invoice waits until approver returns.
F500 AP portal onboarding 3–4 week supplier registration before the first invoice can even be submitted.
Approval bottleneck Multi-level sign-off with no automation. Each level adds days with no visibility into where it is stuck.

Why this keeps happening

None of these exceptions are unusual. Most AR systems treat them as outside the workflow, so they land in someone's inbox every time. Predictable exceptions belong inside the AR workflow, with ambiguous ones routed to a person for review.

Up next: Post 6 covers one of the failures we see most consistently across customer bases: the unreachable contact.

Part of a 10-post series on where B2B AR loses cash, stage by stage.