Your Contractors Are Financing Their Jobs With Your Money

Picture a Monday morning, made up but familiar. The credit manager opens the aging report. A mechanical contractor sits at 74 days past invoice on a $48,000 balance spread across three jobs. One of those jobs got its last delivery in early August. Somewhere in a binder, or in the credit manager’s head, is the date by which a notice has to go out on that job to protect the right to get paid. It might be next week. It might have been last week.

The collector has called the contractor’s office manager four times. Each time, the answer was that the check is waiting on the general contractor. Meanwhile your own vendors want payment on 30 day terms, and the line of credit is carrying the difference.

That’s the quiet arrangement in a lot of supply houses. The contractor gets paid when the GC pays. The GC gets paid when the owner pays. And you’re the bank at the bottom, without the interest income.

A quick word on my background. I’ve never run a credit department. For almost 18 years I ran a digital agency, and now I use AI on the stuck parts of businesses. I won’t tell you how to grant credit. What I can see clearly is how work piles up when one person is juggling hundreds of accounts, dozens of jobs and deadlines that live on paper.

Where the cash and the hours go

Collections at a supply house isn’t one job. It’s four jobs jammed into one chair.

• Deciding who to call. Collectors often work the aging top to bottom or alphabetically. The account that’s slowing down gets the same attention as the one that always pays on day 45.
• Fixing disputes. Many late invoices aren’t late because of money. A missing PO number, the wrong job, a price that doesn’t match the quote, a shortage nobody credited, no proof of delivery. Until somebody fixes it, the contractor’s AP won’t pay it.
• Chasing paperwork. Copies of invoices, signed delivery tickets, statements by job. Collectors spend a lot of time digging up documents so they can ask for money.
• Watching job deadlines. On construction jobs, a supplier’s right to make a claim against a property or a payment bond usually depends on sending notices within set windows. Those windows are often counted from the first or last delivery to that job. They vary by state, by whether the job is private or public, and by your place in the chain.

That last one deserves care. On federal construction jobs that carry a payment bond, for example, the Miller Act gives a supplier who sold to a subcontractor 90 days from the last material it supplied to send written notice to the prime contractor. State rules for private and state public jobs are different, and they change. The deadlines that apply to your jobs, and what to do about them, are for your credit team and your attorney to decide. What a system can do is make sure the right dates are never buried.

What an AI-assisted credit desk looks like

It ranks the day’s work

Every morning the collector gets a ranked list instead of an aging report. Ranking uses amount, days past due, how this account’s payment speed has changed lately, open disputes, and job dates that are getting close. An account that used to pay in 35 days and now takes 60 rises to the top before it hits 90.

It drafts reminders with the right invoices attached

For each account, the system drafts a short, friendly note to the right AP contact, listing the specific invoices by job and PO, with copies and signed delivery tickets attached. The collector reviews, edits if needed and sends. The tone stays human, because these are customers you want back on Monday.

It sorts the replies

When the contractor answers “line 6 never showed up” or “the price doesn’t match the quote,” the system reads it, tags the invoice as disputed, stops reminders on it and routes it to the person who can fix it, with the order and quote attached. Promises to pay get logged with a date so follow-up is automatic.

It keeps job deadlines in front of the credit manager

The system tracks first and last delivery dates per job, along with the job’s type and location. Using deadline rules your credit team and attorney write down, it puts upcoming dates on the credit manager’s calendar well ahead of time. It doesn’t decide whether to send a notice, and it doesn’t send one. It makes sure nobody learns about a deadline after it passed.

Run the numbers

Two formulas. The first is cash freed: days of DSO reduced × average daily credit sales = cash freed. Days sales outstanding is your receivables balance divided by annual credit sales, times 365.

Say, for the sake of the math, a supply house has $30 million in annual credit sales. That’s about $82,200 a day. Say DSO is 58 days, and better prioritization, faster dispute fixes and steady reminders bring it to 50. All of these are made up.

Eight days × $82,200 is about $658,000 of cash that’s no longer sitting in your customers’ bank accounts.

The second is the cost of carrying it: cash freed × your line-of-credit interest rate = annual interest saved. Keep the made-up example and say the line costs 8 percent a year. That’s about $52,600 a year in interest, every year DSO stays down.

Neither number counts bad debt avoided on a job where a deadline would otherwise have slipped. On one large job, that can be bigger than both.

To run it for real, pull three numbers:

1. Annual credit sales, from your financials.
2. Current DSO, from your receivables balance and credit sales.
3. Your line-of-credit rate, from the bank statement.

Picture a Monday, before and after

This is a made-up scene. Picture a credit manager and one collector at a building materials supplier with 600 open contractor accounts.

Before: the collector starts at the top of the aging report and makes calls until lunch. Half the calls end with “send me a copy of that invoice,” which takes another hour to dig up. The credit manager keeps job deadlines on a spreadsheet updated when there’s time, which there usually isn’t.

After: the collector opens a list of 40 accounts ranked for today. Twenty-five drafted reminders are ready, each with the invoices and delivery tickets attached. Six disputes from last week are already with inside sales, flagged with the quote. The credit manager’s calendar shows four jobs with notice dates in the next three weeks, each with the delivery history and the rule that applies. The credit manager decides which ones need action and calls the attorney on one.

Nobody lost judgment. They lost the digging.

What has to be in place first

• Job accounts set up properly. Each job with its address, owner, general contractor, and whether it’s private or public.
• Delivery dates by job. Signed tickets or proof of delivery, tied to the job, retrievable in seconds.
• Written deadline rules. Drafted by the credit team with the attorney, by state and job type, and reviewed when laws change.
• The right AP contacts. For each customer, who actually pays the bills, and how they like to be reached.
• Dispute reasons recorded. So recurring problems, like missing PO numbers, get fixed at the order desk.

Guardrails worth keeping

• The credit manager decides. Credit holds, notices, lien and bond claims, and anything legal stay with the credit team and attorney.
• The calendar is a reminder, not legal advice. Rules come from your attorney. The system just keeps the dates visible.
• No reminders on disputed invoices. Fix the problem first.
• A person sends every message. At least until you trust the drafts, and probably for anything past 60 days.
• Customer financial data stays private. Business-grade tools, access controls, and nothing used to train public models.

How you’ll know it’s working

• DSO, monthly.
• Share of receivables over 60 days.
• Days from dispute raised to dispute resolved.
• Jobs above your dollar threshold with notice dates reviewed on time.
• Collector time per account touched.

Where I’d start

Start with the ranked daily list and drafted reminders, for one collector, on accounts over 45 days. It’s easy to measure, it frees the most hours fastest, and it surfaces the disputes that are really holding up payment. Add job deadline tracking once delivery dates are clean.

If this sounds like your week, send me a note through the contact page.