How must composites be constructed under GIPS, and what common composite construction errors lead to non-compliance?

Under GIPS (Global Investment Performance Standards), composites are aggregations of portfolios managed according to a similar investment mandate, objective, or strategy. Every actual fee-paying discretionary portfolio must be assigned to at least one composite. The fundamental principle is that composites must reflect the firm's investment capabilities accurately and without cherry-picking.\n\nComposite Construction Rules:\n\n`mermaid\ngraph TD\n A[\"All Firm Portfolios\"] --> B{\"Discretionary?\"}\n B -->|\"No\"| C[\"Exclude from composites
(non-discretionary)\"]\n B -->|\"Yes\"| D{\"Fee-Paying?\"}\n D -->|\"No\"| E[\"May exclude from composites
(pro-bono, seed)\"]\n D -->|\"Yes\"| F[\"Must include in
at least one composite\"]\n F --> G{\"Match to Strategy\"}\n G --> H[\"Large Cap Growth Composite\"]\n G --> I[\"Fixed Income Core Composite\"]\n G --> J[\"Balanced 60/40 Composite\"]\n H --> K[\"Include ALL matching portfolios
Cannot exclude poor performers\"]\n`\n\nWorked Scenario:\n\nCompliance officer Ingrid at Ravenswood Capital manages composites for the firm's equity strategies. She reviews the following situations:\n\nSituation 1 -- Portfolio exclusion violation:\nClient Morrison's large cap growth portfolio returned -8.2% while the composite averaged +4.1%. The portfolio manager asks Ingrid to exclude Morrison from the composite because the client imposed unusual cash flow constraints.\n\nIngrid's analysis: Morrison's portfolio has full discretion over security selection and allocation. The cash flow was large but did not remove discretion. Excluding Morrison would violate GIPS. The portfolio must remain in the composite regardless of its poor performance.\n\nSituation 2 -- Mandate change:\nClient Wakefield shifts from large cap growth to balanced 60/40 mid-quarter. GIPS requires moving Wakefield to the balanced composite effective the date the mandate change occurs (or the first full measurement period after, depending on firm policy).\n\nSituation 3 -- New account inclusion timing:\nNew client Thornton opens a large cap growth account on March 15. GIPS requires firms to define a policy for new account inclusion timing (e.g., first full month after opening). If the policy is first full month, Thornton enters the composite on April 1.\n\nCommon Composite Construction Errors:\n\n| Error | Why It Violates GIPS |\n|---|---|\n| Excluding poor performers | Cherry-picking inflates composite returns |\n| Including non-discretionary accounts | Distorts strategy representation |\n| Switching portfolios between composites retroactively | Rewrites performance history |\n| Creating composites with only one portfolio to show best results | Not representative of strategy |\n| Including model/paper portfolios | Only actual portfolios allowed |\n\nMinimum Requirements:\n- Composites must have clear, written definitions\n- All composites must be maintained for a minimum of 5 years (or since inception if shorter)\n- Terminated portfolios must remain in historical composite records\n- Firms must disclose the number of portfolios and total assets in each composite\n\nMaster GIPS composite rules in our CFA Ethics course.