WIP Aging

WIP aging is a report that groups unbilled work by how long it has been outstanding, typically in 30-day buckets, showing which balances are at risk of becoming uncollectable before an invoice is raised. The older a WIP balance, the lower the probability it will be billed and collected at full value.

How to read a WIP aging report

An aging report buckets the total WIP balance by days outstanding:

Bucket	Risk level
0 to 30 days	Normal billing cycle, low risk
31 to 60 days	Yellow flag, review billing status
61 to 90 days	Escalate to engagement manager
90-plus days	Write-off risk, requires partner sign-off

Why aging matters more than total WIP balance

A large WIP balance is not necessarily a problem if most of it is current. A small WIP balance that is 90% over 90 days old is a serious problem. Aging disaggregates the number so the right balances can be acted on. This is also why WIP aging is a stronger leading indicator of write-off exposure than total WIP balance alone, and it connects directly to days sales outstanding in understanding cash collection health.

Common causes of WIP aging

• Billing holds pending client approval that stall invoicing indefinitely
• Time logged by team members who have rolled off the engagement
• Scope disputes where the client contests hours before the invoice is raised
• Fixed-fee milestones that depend on deliverable acceptance the client keeps deferring

How to clear aged WIP

Review all balances over 60 days at each billing cycle. Either raise the invoice, convert the balance to a formal change order, or write it off before it distorts the balance sheet. Carrying stale WIP as an asset overstates revenue recognition and understates true margin.

Partial write-offs are common on engagements that over-ran scope or where the client disputed a portion of hours. In these cases, the firm books the collectible portion as revenue and writes off the remainder in the same period, rather than carrying the full balance into the next quarter.

WIP aging in month-end close

Most firms include an aged WIP review as part of month-end close. The review has two outputs: an invoice run for balances that are ready to bill, and a write-off memo for balances that are not. Both must be signed off before the period closes so that reported revenue and the WIP asset on the balance sheet reflect the same picture. Finance teams that skip this step often discover the discrepancy only at quarter-end, when the correction is larger and more disruptive.