Ten months of slower deliveries: how to sort past-due POs

The number

In the Institute for Supply Management's September 2026 Manufacturing PMI report, the Supplier Deliveries index was 59.0, against 59.3 in August. Above 50, this index means deliveries are getting slower. ISM reads September as deliveries still slowing, at a slightly slower rate than in August, and the index has now pointed to slower deliveries for 10 months.

The same report shows the Inventories index at 48.6, down from 50.6 in August: manufacturers reported raw materials inventories contracting after a month of growth. The Customers' Inventories index was 41.6, which ISM reads as customers' inventories "too low," for a 24th consecutive month.

Slower deliveries, thinner stock, customers with little buffer: the room between "late" and "short" is getting smaller.

What it means on a Monday morning

A Supplier Deliveries reading in the high 50s does not mean every supplier is late. It means more of them are slower than last month than faster. In a plant, that shows up in one place first: the past-due purchase order report gets longer, and stays longer.

Three things happen at the same time when deliveries slow for months:

• The past-due list grows. More open lines drift past their promised dates, and buyers have the same number of hours to chase them.
• Promised dates lose meaning. Suppliers confirm dates they then move. A line can be "on time" in the ERP and still arrive late.
• Planned lead times fall behind. Reorder points set on last year's lead times trigger orders too late, which creates the next round of past-due lines.

Add thinner raw materials inventories, as the Inventories index suggests, and each late order has less stock behind it to absorb the delay.

The trap: sorting by days late

When the list grows, the natural reflex is to sort it by days late and start at the top. That puts the oldest problems first, not the most urgent ones. An order 20 days late for a part with two months of stock can wait. An order 2 days late for a part that runs out on Thursday cannot.

The better question for every line is simple: will this part run out before this order arrives?

Illustrative example, not a customer result

A buyer opens Monday's report with 45 past-due lines. Sorted by days late, the top five are all more than three weeks late, on parts with 40 to 90 days of cover. Sorted by cover, the top five are lines between 1 and 6 days late, on parts with 2 to 5 days of cover and no other open order. Same report, different Monday.

Run it on your own data this week

This takes about 30 minutes with two exports you already have.

1. Export open purchase order lines past their promised date

Item, supplier, open quantity, promised date (or requested date when none was confirmed). Flag lines never confirmed by the supplier.

2. Export stock and usage by item

Usable stock on hand and quantity consumed over the last 12 weeks. Divide usage by 84 to get average daily usage.

3. Compute days of cover and compare

Days of cover = stock / daily usage. For each late line, compare cover with the date you now expect the order. Keep the lines where cover runs out first: they are your shortage risks.

4. Sort by cover and call the top of the list

That is your chase list. Bring the numbers to the call: stock, usage, cover, promised date, days late.

5. Check one lead time

Pick the supplier that appears most often on the list. Compare the lead time in the ERP with the days between order and receipt on its last few deliveries. If the gap is large, you have found lead-time drift, and the reorder points behind it need review.

What to watch next

ISM publishes its October Manufacturing PMI report at the start of November. Two readings matter for buyers: whether Supplier Deliveries stays above 50, which would extend the run of slower deliveries, and whether Inventories keeps contracting. If both hold, expect longer past-due lists with less stock behind them, and give the ranking more attention than the volume.

Guides by ERP for step 1 to 4: SAP, Dynamics 365, Oracle Fusion, Odoo, NetSuite, Epicor.

Where WERISCO fits

WERISCO runs these steps on every open order line at once, from your ERP or the exports you already run, and shows which late or undated supplier orders will leave a part short before they arrive, ranked by severity, with each part's days of cover shown as evidence. Your team decides what to chase; nothing is written back to your ERP. It does not predict supplier delays: it works from the dates you have.

Questions people ask

What does a Supplier Deliveries index above 50 mean?

In ISM's survey, a reading above 50 means more purchasing managers report slower deliveries than faster ones compared with the previous month. It describes direction, not how late any single supplier is.

Does a slower delivery index mean I should hold more stock?

Not across the board. It means you should look at which parts have little cover and late or unconfirmed orders behind them, and review lead times on the suppliers that keep appearing on the list.

How often should the chase list be rebuilt?

Daily when deliveries are slowing. Cover changes every day as stock is consumed, and suppliers move dates.