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Blog · Board and management reporting · Supply chain

Inventory ageing by site: the stock with no movement in 180 days, and the sites that hold it

How a supply chain team reads inventory ageing per SKU per site from the stock and movement files: days since last issue, value in each ageing band, the sites where aged stock concentrates, the SKUs aged at one site and moving at another, the transfer that releases the cash, the write-down exposure at stated bands, and the identity that aged plus moving stock equals the inventory ledger.

The short answerInventory ageing is days since each SKU's last issue at each site, from the stock and movement files, banded: under 90, 90 to 180, 180 to 365, over a year. Value per band per site shows where aged stock sits; the same SKU aged at one site and issuing at another is a transfer that releases cash without a write-down; and the value in the bands above a stated age is the write-down exposure. The identity is that the stock in every band sums to the inventory ledger per site, so the ageing table is the balance sheet cut by time.

A supply chain team reports inventory turns for the network. Inside the network, one site holds two million dollars of stock nobody has issued in a year, and half of it is SKUs another site reorders monthly. The stock and movement files, per SKU per site, show it. This guide sets out ageing bands, the concentration by site, the transfer pairs, the write-down exposure, and the identity.

The measures

Per SKU, per site:

Days since last issue; days since last receipt Ageing band, on days since last issue Value on hand, per band

Per site: value per band; share over 180 days.

Transfer pairs:

Aged at site A, issuing at site B, aged quantity ≤ k × B's monthly usage

The rows you need

  • Stock file: SKU, site, quantity on hand, value, last receipt date.
  • Movement file: SKU, site, issue date, quantity.
  • Write-down policy: band, rate.

SKU and site identifiers only.

The identity

Σ bands' value per site = inventory ledger per site

A SKU on hand with no movement record at all is in the never-issued band, counted, not dropped.

A worked view

Site Inventory Under 90 90 to 180 180 to 365 Over 365 Share over 180
Plant A $8.4m $5.9m $1.4m $0.7m $0.4m 13%
Plant B $6.1m $2.2m $1.1m $1.4m $1.4m 46%
Plant C $4.0m $3.1m $0.6m $0.2m $0.1m 8%

Plant B holds nearly half its inventory in stock nobody has issued for six months.

Transfer pairs, Plant B

SKU Aged at B Days since issue at B Issuing at B's monthly usage at that site Transfer?
K-104 $180,000 290 Plant A $40,000/month Yes: 4.5 months of A's usage
K-227 $95,000 410 Plant C $3,000/month No: 32 months of C's usage; write down
K-330 $61,000 220 Plant A $22,000/month Yes

Two transfers release two hundred and forty thousand dollars of Plant B's aged stock into a site that will use it in months. The third is a write-down whatever happens.

Write-down exposure

Site Over 180, not transferable Policy rate Exposure
Plant B $2.3m 50% over 365; 25% 180 to 365 $0.9m

The number that gets the transfer list worked before quarter end.

Where it goes wrong

Network turns only. Plant B inside a healthy average.

Ageing on receipt date. Healthy slow lines flagged; never-issued lots missed.

Transfers without the usage check. The aged stock moves and ages elsewhere.

Write-down not on the page. The list is worked after finance books it.

Every month, ageing per site and the transfer list

Mapped once, the stock and movement files and the write-down policy produce the bands per site, the transfer pairs, the exposure and the identity every month. Covirage builds this from the exports as they are. The supply chain page describes the setup, and the lead time variability guide covers why some of the aged stock was bought in the first place.

Questions people ask

Why days since last issue rather than days since receipt?

Because a SKU received a year ago and issuing weekly is not aged; it is a slow, healthy stock line. Days since last issue measures whether anyone is using it. Days since receipt is shown beside it for the lots that never issued at all.

How is a transfer identified?

A SKU in the over-180 band at one site with issues in the last 30 days at another, where the aged quantity is under a stated multiple of the issuing site's monthly usage. The report lists the pairs with the value and the usage, and the planner confirms. Moving a year of stock to a site that uses a month's worth is not a transfer; it is the same problem elsewhere.

What is the write-down exposure?

Value in the bands the company's own policy writes down, at the policy's rates, per site. It is what finance will book if nothing moves, and it is the number that gets the transfer list worked.