Compliance is claimed at firm level, not per product, and requires that all fee-paying discretionary portfolios be included in at least one composite. That requirement is the point: it prevents a firm from showing only the accounts that did well, addressing survivorship-bias directly.
The standards specify time-weighted return methodology, minimum history, treatment of fees and cash flows, and required disclosures including benchmark, dispersion and composite definition. Verification by an independent firm is separate from the claim of compliance, and the distinction is often blurred in marketing.
For an allocator, GIPS compliance raises confidence in comparability but does not validate the strategy or guarantee accuracy. Ask whether the firm is verified, and read the composite definition to see what is actually included. See performance-reporting.
Related: performance-reporting, time-weighted-return, survivorship-bias, benchmark, backtesting, fiduciary-duty