Your Vendor Spend Is More Concentrated Than You Think

The Risk Hiding in Your AP

Ask a contractor how many vendors they use. They'll guess 50, maybe 100. Pull the actual data and the number is usually 3-10x higher. But here's the catch: the vendor count doesn't matter. What matters is how that spend is distributed.

Across the 2,200+ contractors I've reviewed — representing over $4 billion in accounts payable — the pattern is consistent: most contractors have a long tail of vendors but a short list of suppliers that receive the majority of their spend. That concentration creates risk most contractors never think about.

What the Data Shows

From analyzing vendor and AP data across the dataset, the spread is enormous:

That last row is the standout: $54,000 in average spend per vendor. That's not a long tail — that's concentrated purchasing from a relatively small number of high-value suppliers. When one of those suppliers raises prices, delays a shipment, or goes out of business, the impact ripples through every job in progress.

Compare that to the first row: $2,870 per vendor across 9,300 vendors. Massively distributed spend. More resilient, but potentially less efficient on pricing leverage.

The Three Types of Vendor Concentration Risk

1. Single-Source Equipment Dependency

HVAC contractors selling Trane, Carrier, or York equipment often have 60-80% of their equipment spend with a single manufacturer. That's fine when the relationship works. It becomes a crisis when:

• The manufacturer raises prices mid-season and you've already quoted jobs at old pricing
• Lead times stretch from 2 weeks to 12 weeks (we all remember 2021-2022)
• The manufacturer changes their dealer program and you lose preferred pricing

From the product catalog data in the dataset: Trane averages $1,498 per product, Carrier $1,370, York $1,242. These are high-ticket items. A 10% price increase from your primary equipment supplier on $2M in annual equipment purchases is a $200K margin hit.

2. Subcontractor Over-Reliance

Contractors that outsource heavily — and some in the dataset have 2,300+ subcontractor vendors — face a different concentration risk. If your top 3 subcontractors handle 60% of your outsourced work, you're one labor shortage away from missing deadlines.

The data shows this clearly with national maintenance companies that manage a network of subs across geographies. The ones with thousands of subcontractors are essentially general contractors running thin margins on pass-through work. At 24% average margin on subcontractor line items — the thinnest margin of any cost type — there's no room for surprises.

3. Supply House Dependency

Most contractors buy materials from 2-3 local supply houses. The pricing is negotiated, the account terms are established, and the parts runner knows where everything is. That convenience creates lock-in.

When your primary supply house knows they're your only source, pricing leverage shifts to them. A 3-5% annual price increase that "matches market conditions" adds up fast on $500K+ in annual materials spend.

How to Quantify Your Risk

Here's a quick exercise:

1. Pull your AP by vendor for the last 12 months. Sort by total spend, highest to lowest.
2. Calculate concentration. What percentage of total spend goes to your top 5 vendors? Your top 10?
3. Flag single-source dependencies. Are there any vendors where you have no alternative? What would happen if they raised prices 15% tomorrow?

Rules of thumb from what I've seen across hundreds of contractors:

The Margin Impact

Vendor concentration doesn't just create supply risk — it affects your margins directly.

From the quote line pricing analysis across the dataset:

If your business is heavy on equipment and subcontractor pass-through, you're running on thin margins that are controlled by your vendors, not by you. The contractors with the highest margins in the data are labor-heavy service companies — their biggest cost (technician time) is internal and controllable.

This is one reason why the most profitable contractors shift their revenue mix toward service and maintenance: the margins are higher because they're less vendor-dependent.

What Smart Contractors Do

Dual-source critical materials. Don't buy all your copper, refrigerant, or ductwork from one supplier. Even if your primary supplier is 5% cheaper, having a secondary source means you have leverage when they raise prices and a backup when they can't deliver.

Negotiate annually, not reactively. The best-run contractors in the data renegotiate supply house terms every year. Volume commitments in exchange for price locks. Extended payment terms (Net 45 instead of Net 30) to improve cash flow. Early-pay discounts (2/10 Net 30) when cash position allows.

Track material cost as a percentage of revenue. If your materials-to-revenue ratio is creeping up quarter over quarter, either your vendors are raising prices or your estimating isn't keeping pace. This is the kind of trend a fractional CFO catches in a monthly financial review.

Build subcontractor depth. For every critical trade you outsource, have at least 3 qualified subs on your approved vendor list. Price-check subs annually. The ones in the dataset with thousands of subcontractors aren't managing all of them actively — they have 10-15 core subs and a deep bench for overflow.

When Concentration Is Actually Fine

Equipment dealer relationships are inherently concentrated. If you're a Carrier dealer, you sell Carrier. That's the business model. The risk isn't the manufacturer relationship — it's failing to adjust pricing when the manufacturer adjusts theirs. Build escalation clauses into project quotes that cover manufacturer price changes.

Specialized subcontractors may be the only option in your market. If there's one controls contractor in your metro area, you're single-sourced by market reality, not by choice. In that case, the fix is a strong contractual relationship with pricing protection, not diversification.

Under $3M in revenue, vendor management complexity usually isn't worth formalizing. You have 20-30 vendors, you know them all personally, and the relationships are direct. The concentration risk framework kicks in when you're doing $5M+ in AP and the vendor count exceeds what one person can track by memory.

---

The Bottom Line

Most contractors think about sales, margins, and cash flow. Few think about the supply chain that feeds all three. When your top 5 vendors control 60%+ of your spend, a single pricing change or supply disruption can wipe out a quarter's profit.

The fix isn't eliminating concentration — it's knowing where it exists, having alternatives ready, and negotiating from a position of information. Pull your AP data, run the numbers, and know your exposure.

Q: How does Level help with vendor analysis? A: We build a vendor spend dashboard from your QuickBooks AP data showing concentration ratios, spend trends by vendor, and margin impact. We flag single-source dependencies and track material cost inflation against your revenue growth. The first audit is free.

Q: Should I consolidate or diversify vendors? A: It depends on your leverage. If consolidating spend with one supplier gets you 10% better pricing, the savings may outweigh the concentration risk — as long as you have a backup qualified and ready. Diversify for resilience; consolidate for savings. The best contractors do both strategically.