Supplier Concentration Risk Assessment Checklist for Australian Business Buyers

A supplier due diligence checklist for buying a business in Australia walks through every step needed to assess how dependent a business is on its key suppliers — and whether those relationships will survive a change of ownership. Most trades and service businesses are more reliant on a handful of suppliers than the seller will volunteer. Trade accounts, credit terms, and pricing arrangements don't automatically transfer to a new owner, and the ones that don't often don't surface until three months after settlement when the margins start compressing.

If you've been reading about supplier concentration risk when buying a business, you'll know the core problem: a painting contractor's margin may depend on a trade account held in the seller's personal name; a landscaping business's cash flow may depend on 60-day credit terms negotiated informally over a decade. These are real commercial assets — they just don't appear on the balance sheet, and they're invisible in the information memorandum.

This checklist sits within Module 5 of the Playbook and works alongside the broader due diligence process for buying a small business. Use it in parallel with the operational due diligence checklist rather than instead of it.

Why Supplier Due Diligence Gets Left Until Last

Most buyers spend their due diligence budget on financials, leases, and customer lists. Supplier relationships feel like operational detail — something to sort out post-settlement when there's more time and less going on. That's the wrong order.

A buyer I know acquired a concreting business without confirming whether the aggregate supplier would honour existing volume pricing with a new owner. The supplier was friendly about it (they're usually friendly) but the pricing had been discretionary all along, tied to a relationship between the principals built over twelve years. The new owner spent six months at higher materials costs while they rebuilt purchase history to qualify for equivalent terms. It wasn't on any checklist, and it wasn't in the IM.

A few things to do before you ever open the accounts payable ledger:

Ask the seller directly about trade accounts. Not "do you have trade accounts" — everyone does. Ask: "Which of your trade accounts are in your personal name?" The pause before the answer is informative.

Map the concentration before the deep dive. Pull the creditor ledger for 24 months and calculate each supplier's share of total purchases. Any single supplier above 30% needs individual investigation. Above 50% is a material deal issue.

Understand what "great relationship" actually means. Sellers often mention supplier relationships as a selling point. That's the moment to ask whether those relationships are documented, whether accounts are in the business entity, and whether pricing arrangements are in writing. You'll quickly separate the real asset from the social lubricant.

The full checklist below covers all four phases: initial screening, confirmatory due diligence, pre-settlement verification, and post-settlement management. It includes a risk scorecard to help you quantify each supplier's concentration risk and use it in price negotiations where relevant. See also: due diligence checklist for buying a business in Australia and the customer concentration risk assessment — the two risks often travel together.

Supplier Concentration Risk Assessment Checklist

Use this checklist across four stages. Check each item as you complete it. The risk scorecard at the end lets you quantify exposure per supplier and reflect it in your offer structure.

Phase 1: Initial Supplier Screening (Before Signing the LOI)

These checks happen before you commit to a full due diligence engagement. They help you decide whether supplier risk is a material issue worth investigating in depth — and they cost you nothing but a direct conversation with the seller.

Ask the seller to name their top five suppliers by spend. Note whether they can answer from memory, or whether they need to check records. Uncertainty here is a signal.
Ask directly: "Are any of your trade accounts in your personal name rather than the business name?" A long pause or a deflection is more informative than the actual answer.
Ask whether the business receives any rebates, volume discounts, or preferred pricing from suppliers. If yes, ask on what basis those arrangements exist and whether they're documented.
Ask whether any suppliers have exclusivity arrangements — either where the business is the exclusive or preferred buyer for a supplier, or where the supplier restricts who else the business can buy from.
Check whether the information memorandum mentions supplier relationships as a business strength. If it does, those relationships need independent verification in confirmatory DD.
Ask: "What would happen to this business if your main supplier stopped selling to you or doubled their prices?" The seller's answer tells you how dependent the business actually is.
Preliminary assessment: is supplier concentration likely to be a material issue? Flag yes / no / uncertain to inform your LOI scope and due diligence budget.

Phase 2: Confirmatory Supplier Due Diligence (After LOI, Access to Records)

These steps require access to the business's financial records. They should be completed before you move to confirmatory due diligence on other matters — supplier risk can change the deal structure.

2A: Supplier Spend Analysis

Request the full accounts payable creditor report for the last 24 months, showing total payments per supplier by month.
Calculate each supplier's share of total purchases over the full period. Record the top 10 suppliers and their percentage of total spend.
Flag any supplier above 25% of total purchases for individual review.
Flag any supplier above 50% of total purchases as high concentration — this becomes a priority item requiring resolution before you proceed.
Check whether any significant supplier in prior years is absent from recent data. This can indicate a relationship that ended, terms that changed, or a product switch worth understanding.
Compare materials costs as a percentage of revenue over three years. An unexplained improvement in this ratio — margins getting better without obvious explanation — may reflect favourable supplier terms tied to the current owner.

2B: Account Ownership and Terms

For each flagged supplier, confirm whether the account is held in the business entity name (ABN) or in the seller's personal name. This is the single most important check.
Request copies of all trade account agreements for suppliers accounting for more than 20% of total purchases.
Review the credit terms on each flagged account: standard 30-day versus extended 60- or 90-day terms. Extended terms that were granted personally to the seller may not transfer.
Identify any rebate agreements, volume pricing schedules, or preferred supplier arrangements. Request the documentation and check whether these are assignable.
Confirm whether any supplier agreements include assignment clauses permitting transfer to a new owner — or whether they require fresh negotiation after a change of control.
Request the last 12 months of supplier statements for the top three suppliers to verify payment history, current balance, and standing.
Ask the seller whether any supplier has ever raised the change of ownership as a reason to vary terms. Their answer tells you whether this conversation has already happened.

2C: Subcontractor Review

List all subcontractors used in the last 12 months and the total spend per subcontractor.
Calculate the percentage of total job delivery that flows through each subcontractor. A single subcontractor handling more than 20% of delivery is a form of supplier concentration.
Flag any subcontractor above 20% of total delivery for individual review.
Confirm whether key subcontractors are under written agreements or informal arrangements. Long-tenure informal arrangements are common in trades, and they often don't survive ownership changes.
Assess whether key subcontractors work primarily or exclusively for this business, or whether they have independent client bases. Exclusivity is an asset that can also walk out the door.
Ask the seller whether key subcontractors have been told about the sale and what their likely reaction is.

2D: Pricing and Margin Risk Quantification

For each high-concentration supplier, model the impact on gross margin if their pricing reverts to standard market rates. Run two scenarios: moderate repricing (10-15%) and full market rate.
Translate the margin impact into a dollar impact on normalised EBITDA. This becomes your quantified risk figure for price negotiations.
For each flagged supplier, identify at least two alternative suppliers in the market who could serve the business at comparable pricing. Note lead times and whether existing customer commitments could be met during a transition.
Assess the cost and time required to shift spend to an alternative supplier. Some industries require supplier qualification processes or product approval steps before a switch is practical.
Ask the seller: "If you had to replace this supplier tomorrow, what would that cost the business in the first year?" This is a useful cross-check on your own modelling.

Phase 3: Pre-Settlement Supplier Verification

These steps happen after you've decided to proceed with the acquisition and are heading toward exchange and settlement.

3A: Supplier Introductions and Commitments

For each high-concentration supplier, ask the seller to facilitate a formal introduction before settlement — either a meeting, a phone call, or at minimum a written introduction.
Where the supplier has an account manager or relationship manager, ensure the introduction is to that person specifically, not just the general accounts line.
For accounts currently in the seller's personal name, confirm the process for establishing a new account in the buying entity's name. Some suppliers will transfer; others require a fresh credit application.
For accounts requiring a new credit application, begin the application process before settlement if the seller and supplier will permit it. Start from a position of strength rather than urgency.
Request a written confirmation from each high-concentration supplier that they intend to continue the commercial relationship with the new owner. Not all suppliers will provide this — many will say it's company policy not to — but it's worth asking. The response is informative.
For key subcontractors, ask the seller to make a personal introduction before settlement. Even a brief call is enough to establish that the new owner is a known entity.

3B: SPA and Settlement Protections

Ensure the Sale and Purchase Agreement includes a vendor warranty that the seller is not aware of any material changes to key supplier terms in the 12 months prior to settlement.
Include a specific warranty that no key supplier has been informed of, or has raised concerns about, the change of ownership during the sale process.
If supplier risk is material and cannot be resolved through commitments, negotiate an earn-out provision tied to the business maintaining its key materials cost base in the 12-24 months post-settlement.
Add supplier introductions as an explicit deliverable to the seller handover period — documented in the SPA or a side letter, not just discussed verbally. Specify: which suppliers, what form of introduction, and within what timeframe after settlement.
Add the supplier introduction items to your seller handover checklist so they're tracked in the transition.
For any supplier rated as high risk (see scorecard below), seek legal advice on whether a condition precedent to settlement is warranted — i.e., settlement is conditional on the supplier confirming continuation of the relationship.

Phase 4: Post-Settlement Supplier Risk Management (First 90 Days)

Week 1: Introduce yourself in writing to all top suppliers. A brief email or letter confirming the ownership change and your intent to maintain the relationship sets the right tone.
Week 2: Confirm account details, credit limits, and trading terms in writing with each major supplier. Don't assume — get it confirmed on your new letterhead.
Week 4: Review invoices from each major supplier against pre-acquisition pricing. Address any discrepancies immediately — don't let repricing bed in silently.
Month 2: Begin building a relationship with at least one alternative supplier for each high-concentration supplier. You don't need to move spend; you need an option.
Month 2: If trade accounts needed to be transferred or re-established, confirm that credit terms have been reinstated in full. Temporary reduced terms during a new account period are common and worth tracking.
Month 3: Reassess supplier concentration against your pre-acquisition model. Have relationships bedded in as expected? Are there any emerging dependencies you didn't anticipate?
Month 3: Add supplier concentration metrics to your ongoing KPI dashboard. The KPI checklist for new trades business owners has a framework for setting this up.

Supplier Risk Scorecard

Complete this scorecard for each supplier flagged in Phase 2. Score each factor from 1 (highest risk) to 5 (lowest risk).

Factor 1: Account Ownership Score ___ / 5.

Score 1 — Account is in the seller's personal name; no transfer process identified and supplier has not been contacted.
Score 3 — Account is in the business entity name but credit terms are discretionary and may be reviewed on a change of ownership.
Score 5 — Account is in the business entity name with documented terms; no transfer required and supplier has confirmed continuation.

Factor 2: Pricing Documentation Score ___ / 5.

Score 1 — Pricing is entirely informal, based on personal relationship, no documentation exists.
Score 3 — Pricing is partially documented (email correspondence, price lists) but no formal agreement with assignment provisions.
Score 5 — Formal pricing agreement exists, is in the business name, and includes an assignment clause permitting transfer to a new owner.

Factor 3: Credit Terms Score ___ / 5.

Score 1 — Extended credit terms (60+ days) are discretionary and were granted personally to the seller; standard new-account terms are 14 days.
Score 3 — Credit terms are in the business name but at the upper end of what the supplier typically offers; some repricing risk exists.
Score 5 — Standard market credit terms apply; nothing suggests a new owner would be treated differently from any established customer.

Factor 4: Supplier Commitment Score ___ / 5.

Score 1 — Supplier has not been informed of the sale; cannot be approached before settlement; relationship is entirely personal to the seller.
Score 3 — Supplier is aware of the sale and has expressed willingness to continue the relationship verbally; no written confirmation obtained.
Score 5 — Supplier has confirmed in writing that they will continue the commercial relationship with the new owner on equivalent terms.

Factor 5: Alternative Options Score ___ / 5.

Score 1 — No viable alternative supplier exists in the market; switching would require product reformulation or significant lead times.
Score 3 — Alternative suppliers exist but at meaningfully higher pricing or with limited capacity; a switch would hurt margins for 6-12 months.
Score 5 — Multiple alternative suppliers available at equivalent pricing with short lead times; switching cost is low.

Total Score: ___ / 25

20-25 points — Low risk. Proceed with standard post-settlement monitoring.
14-19 points — Moderate risk. Ensure written commitments are in place before settlement. Consider an earn-out on materials cost if commitment cannot be obtained.
8-13 points — High risk. Reflect in purchase price or earn-out structure. Escalate with your legal and financial advisors before proceeding.
7 or fewer — Very high risk. Reassess whether the deal economics hold without this supplier relationship. Do not settle without either a written commitment from the supplier or a price adjustment that reflects the downside scenario.

This checklist is part of Module 5 (Due Diligence) of the Leveraged Worker Playbook. Related resources: customer concentration risk assessment, operational due diligence checklist, due diligence checklist for buying a business in Australia, and seller handover checklist.

Supplier Concentration Risk Assessment Checklist for Australian Business Buyers

Why Supplier Due Diligence Gets Left Until Last

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