The Math Nobody Does Until It's Too Late
A contractor you've worked with for three years stops paying. Maybe a project went sideways. Maybe their own client stopped paying them. Maybe they filed Chapter 11 and your invoices are now in a pile with every other creditor's.
The balance is $15,000. Your credit manager writes it off. Your controller adjusts the books. And most companies move on, treating it as a $15,000 loss.
It's not a $15,000 loss. Not even close.
Construction industry net profit margins hover in the single digits. Commercial contractors average 3.4%. Distributors typically run 3% to 5%, depending on the segment. At those margins, every dollar of bad debt requires a massive amount of new revenue to replace.
Here's the formula: Lost amount ÷ net profit margin = revenue needed to recover.
$15,000 ÷ 5% = $300,000 in new revenue.
$15,000 ÷ 3.4% = $441,000 in new revenue.
That's not theoretical. That's how much new business your sales team has to close — and your operations team has to deliver — just to get back to the position you were in before that one account went bad.
The Recovery Math at Scale
| Write-Off Amount | Revenue to Recover (at 3% margin) | Revenue to Recover (at 5% margin) | Revenue to Recover (at 8% margin) |
|---|---|---|---|
| $5,000 | $167,000 | $100,000 | $62,500 |
| $15,000 | $500,000 | $300,000 | $187,500 |
| $50,000 | $1,670,000 | $1,000,000 | $625,000 |
| $100,000 | $3,330,000 | $2,000,000 | $1,250,000 |
| $1,000,000 | $29,000,000+ | $20,000,000 | $12,500,000 |
At 3.4% margins, a $1 million bad debt requires $29 million in new revenue to recover. That's not a write-off. That's a business-threatening event.
And the industry average isn't reassuring. Bad debts average 8% of all B2B credit sales in the United States. U.S. companies write off an average of 4% of accounts receivable annually. For a distributor doing $20M in revenue with $4.5M in receivables, 4% write-offs are $180,000 per year — requiring $3.6M to $6M in new sales just to break even on losses.
Why Construction Credit Is Uniquely Dangerous
Extending trade credit is a competitive necessity for construction distributors. Contractors expect NET 30, NET 60, sometimes NET 90. If you don't offer terms, the distributor down the road will.
But construction credit carries risks that other industries don't face.
Project-based volatility. A contractor's financial health can swing dramatically from project to project. A company that paid you reliably for two years can suddenly be in trouble because one big job went over budget, an owner held payment, or a general contractor disputed a change order. Their cash flow crisis becomes yours.
Long payment cycles amplify exposure. When terms are NET 60 or NET 90, your outstanding balance with a single customer can grow large before any warning signs appear. By the time you realize there's a problem, you might have three months of invoices exposed.
Cascading failures. Construction payment problems rarely stay contained. An owner holds payment on a project. The GC delays the sub. The sub delays you. And suddenly, a dispute you had nothing to do with — between parties you've never met — is the reason your invoices aren't getting paid.
Contractor insolvency risk. Building materials companies face particularly high insolvency risk due to the debt ratios inherent in the business model. A contractor who takes on one bad project can cascade into insolvency, and the suppliers who extended credit are left holding the bag.
87% of businesses report being paid after their invoice due date. In construction, the question isn't whether you'll deal with late payments — it's whether a late payment turns into no payment.
The "Good Customer Gone Bad" Problem
This is the scenario that keeps credit managers up at night. It's not the new customer you've never worked with. It's the contractor who's been solid for years.
They paid on time — or close to it — for 24 months. You extended their credit limit because they earned it. They're now running $40,000 to $60,000 in open invoices at any given time.
Then one project goes wrong. Maybe the owner disputes the GC's pay application. Maybe the GC slow-pays the sub because their own cash is tight. Maybe the contractor underbid a job and is bleeding margin. Whatever the cause, your invoices suddenly age from 30 days to 60, then to 90, then to 120.
By the time the pattern is visible in your aging report, you're already deeply exposed. The write-off isn't $5,000. It's the accumulated balance of a customer you trusted precisely because they'd earned that trust.
This is why credit risk in construction isn't just about screening new customers. It's about monitoring existing ones — continuously, based on real payment data, not annual reviews.
Five Credit Risk Controls That Actually Work
1. Run Credit Checks Before Extending Terms — Every Time
Not just for new customers. Run updated credit checks annually on any account with a credit limit above $10,000. Payment behavior changes. A contractor who was solid last year may be overextended this year. A five-minute check can prevent a five-figure loss.
2. Set Credit Limits Based on Margin, Not Revenue
A $50,000 credit limit feels reasonable for a contractor who orders $200,000 a year. But at 4% margins, a $50,000 loss requires $1.25M in new revenue to recover. Set limits relative to what you can afford to lose, not what the customer wants to buy.
3. Create Aging-Based Triggers
Don't wait for a 90-day past-due report to take action. Set automatic triggers: at 15 days past due, send a reminder. At 30 days, escalate to a phone call. At 45 days, hold new orders until the balance is current. At 60 days, involve your credit manager directly. The earlier you act, the higher the recovery rate.
4. File Preliminary Notices on Every Project
A preliminary notice isn't just a lien protection tool — it's a signal. It tells the GC, the owner, and the contractor that you're tracking the project and protecting your position. Suppliers who file preliminary notices get paid faster and more consistently than those who don't.
5. Consider Trade Credit Insurance
Trade credit insurance costs 0.1% to 0.3% of insured sales. For a distributor doing $20M in revenue, that's $20,000 to $60,000 per year. Compare that to a single $50,000 write-off that would require $1M+ in new revenue to recover. The math often favors the insurance — especially for accounts in the $25,000+ range.
The Early Warning Signs
Bad debt rarely arrives without warning. The signals are usually there — buried in your AR data weeks or months before the write-off happens. Here's what to watch for:
Payment timing drift. A customer who used to pay at 25 days starts paying at 40, then 55. The amounts are the same. The timing is shifting. That's the earliest and most reliable signal.
Partial payments. They start paying $8,000 on a $12,000 invoice. Or they pay the oldest invoice but let the newer ones age. Partial payments often indicate cash flow stress — they're paying enough to keep the account active but not enough to stay current.
Dispute frequency increases. A customer who never disputed invoices suddenly has questions about every third bill. Sometimes it's legitimate. Often, it's a delay tactic — buying time they don't have.
Changes in ordering patterns. A customer who ordered consistently — $15,000 to $20,000 per month — suddenly drops to $5,000 or places one large order after weeks of silence. Both patterns can signal financial distress.
Industry chatter. If your sales reps hear that a contractor lost a big bid, had a project cancelled, or is laying off crew, that information is relevant to your credit exposure. Build a feedback loop between your sales team and your credit team.
The best credit policy in the world can't help if your AR data is two weeks stale. Real-time visibility into who owes you, how much, and how their payment behavior is trending is the difference between catching a problem at $5,000 and discovering it at $50,000.
