Provider Concentration Ratio

Provider Concentration Ratio is the share of an agency's live client delivery that depends on a single model vendor, measured in billable projects rather than API keys. A retainer running three client builds on one provider's API looks diversified on an invoice and is not: a pricing change, a deprecation, or a guardrail shift hits all three at once. The ratio matters because infrastructure cost is a pass-through that agencies rarely reprice mid-contract, so a vendor move lands directly on margin. The practical test is to count distinct providers behind each deliverable and flag any client where one vendor carries more than half the inference load. Routing layers such as OpenRouter, Portkey, and Helicone exist to make that count adjustable without rewriting application code. The same discipline applies to compute: industry executives expect only 7 to 10 of hundreds of AI cloud providers to survive consolidation, so GPU capacity booked with a single neocloud carries the same concentration risk as a single-model stack.