The Herfindahl-Hirschman Index applied to affiliate publisher GMV — sum of squared GMV share percentages. Measures publisher concentration risk. Benchmarks: below 1,500 = healthy diversification; 1,500-2,500 = moderate risk; above 2,500 = high risk. Action: if HHI exceeds 2,000, prioritize Tier 2 publisher development. Simpler proxy: if top-5 publishers generate >60% of program GMV, concentration risk is meaningful.
Related Resources