Supplier Concentration Risk: Top 1 Supplier = 60% of Purchases = Business Stops If They Stop
- How to Measure Supplier Concentration
- The Financial Risk of Concentration
- Diversification Without Losing Volume Discounts
- AskBiz Supplier Concentration Analytics
- Calculating HHI Step by Step From Your Purchase Ledger
- Worked Example: The Cost of Waiting Too Long to Diversify
- Common Mistakes in Managing Supplier Concentration
Manufacturer: total purchases SGD 800K/year. Supplier A: SGD 480K (60%). Supplier B: SGD 160K (20%). Supplier C: SGD 160K (20%). Supplier A raises prices 10% (SGD 48K increase) — you have no leverage to negotiate (too dependent). Supplier A has quality issue Q3: production delays 3 weeks = SGD 150K missed orders. Diversify: reduce Supplier A to 40% (SGD 320K), add Supplier D SGD 160K. New leverage: can credibly threaten to shift 20% more = Supplier A offers 5% discount = SGD 24K saving.
- How to Measure Supplier Concentration
- The Financial Risk of Concentration
- Diversification Without Losing Volume Discounts
- AskBiz Supplier Concentration Analytics
- Calculating HHI Step by Step From Your Purchase Ledger
How to Measure Supplier Concentration#
Herfindahl-Hirschman Index (HHI) for suppliers: sum of squared market share percentages. Single supplier 100%: HHI = 10,000 (monopoly risk). Two suppliers 50/50: HHI = 5,000. Four suppliers 25% each: HHI = 2,500. Target for supply chain resilience: HHI <3,000 (no single supplier >40%). Simple rule: if your top supplier is >40% of total purchases, you have concentration risk. If >60%: critical risk.
The Financial Risk of Concentration#
Three failure modes: (1) Price increases — no negotiation leverage when dependent. Supplier raises 10%: you absorb it (can't switch quickly). SGD 480K spend × 10% = SGD 48K forced increase. (2) Supply disruption — factory fire, port strike, quality hold: production stops. Cost: missed orders × margin = SGD 150K-300K depending on inventory buffer. (3) Relationship deterioration — supplier prioritises other customers in shortage. You get allocation cuts first.
Diversification Without Losing Volume Discounts#
Reducing concentration doesn't mean losing volume discounts. Strategy: (1) secondary supplier qualification (identify Supplier D, run small trial orders at 10-15% of spend), (2) negotiate volume commitment with Supplier A at lower level (commit SGD 300K/year minimum for discount, vs current SGD 480K with no contract), (3) build safety stock of 4-6 weeks for critical components (buffer against disruption). Cost of safety stock: carrying cost ~25%/year of buffer value. For SGD 80K safety stock: SGD 20K/year — worth it vs SGD 150K disruption risk.
AskBiz Supplier Concentration Analytics#
Tracks purchase orders and invoices by supplier. Calculates concentration ratio and flags risk. "Supplier concentration: Supplier A 58% (HIGH RISK — above 40% threshold). Supplier B 22%, Supplier C 20%. HHI: 3,828 (elevated). Actions: (1) Qualify alternative for Supplier A's 3 key SKUs — identify supplier from ASEAN trade directory. (2) Reduce Supplier A to 40% over 6 months (shift SGD 160K to new supplier). (3) Safety stock for Supplier A's top 5 items: SGD 40K buffer = SGD 10K annual carrying cost vs SGD 200K disruption risk. Trend: supplier concentration up 5% since last quarter (Supplier A gained more share — investigate why)."
Calculating HHI Step by Step From Your Purchase Ledger#
Pull 12 months of purchase spend grouped by supplier. Calculate each supplier's % share of total spend, square each percentage (expressed as a whole number, e.g. 60% = 60, squared = 3,600), and sum the squares across all suppliers. Three suppliers at 60%, 25%, 15% gives HHI = 3,600 + 625 + 225 = 4,450 — well above the 3,000 resilience threshold. The same total spend split 40%/35%/25% gives HHI = 1,600 + 1,225 + 625 = 3,450, still elevated but meaningfully safer. This calculation takes minutes once your purchase data is grouped by supplier, and re-running it quarterly catches concentration creeping upward before a single supplier accidentally becomes 60%+ of spend through gradual, unplanned reliance rather than a deliberate sourcing decision.
Worked Example: The Cost of Waiting Too Long to Diversify#
An electronics assembler let concentration on its main component supplier drift from 45% to 68% over 18 months, simply because that supplier consistently had the best price and lead time, and nobody tracked the ratio actively. When the supplier's factory experienced a fire-related production halt, the assembler had no qualified backup for the affected components and faced an 11-week gap before an alternative supplier could be onboarded and quality-tested. Lost production during that window: approximately SGD 340,000 in missed customer orders, several of which went to competitors permanently. A retrospective analysis showed that maintaining a qualified secondary supplier at just 15-20% of volume — which would have cost an estimated SGD 8,000/year in slightly higher blended component costs — would have allowed a much faster ramp-up and likely limited the disruption to 2-3 weeks and under SGD 60,000 in lost orders. The insurance-like cost of diversification was a fraction of the realised disruption cost.
Common Mistakes in Managing Supplier Concentration#
The first mistake is treating concentration as acceptable simply because the dominant supplier has always been reliable — past reliability doesn't protect against a factory fire, a geopolitical export restriction, or a change in the supplier's ownership and priorities, all of which can happen without warning. The second mistake is qualifying a backup supplier on paper but never placing real orders with them — a backup that's never actually produced for you at scale is not a tested backup, and the ramp-up time in a crisis will be far longer than expected. The third mistake is negotiating exclusivity or minimum-volume commitments with a dominant supplier without also formally maintaining a qualified alternative, which locks in the concentration risk in exchange for a price discount that may not cover the cost of a future disruption. AskBiz recalculates supplier HHI automatically from purchase order data each month, so concentration creep gets flagged as a trend rather than discovered only after a disruption has already occurred.
People also ask
How many suppliers should a small business have per category?
Rule of thumb: 2-3 qualified suppliers per critical category. One primary (70% of orders, best price/service), one secondary (20-25%, kept warm with regular orders), one backup (5-10%, or just qualified but not ordering). Cost of qualification (audits, samples, testing): SGD 2K-10K per supplier — worth it for categories >SGD 100K/year.
What if my supplier doesn't want me to split orders?
Most suppliers understand dual-sourcing is standard practice. Frame it as: "we're growing and need backup capacity." If they object: negotiate contractual commitments (guaranteed minimum orders) in exchange for exclusivity — but only if they offer meaningful price reduction (>5-8%) to justify the dependency risk.
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