Customer-based corporate valuation (CBCV) links customer behavior with firm value by using acquisition, retention, purchasing, and spending to forecast the revenues and cash flows underlying corporate valuation. This study systematically reviews the peer-reviewed CBCV literature to assess its conceptual development, methodological approaches, empirical validation, and unresolved valuation problems. Searches across four business databases identified 134 records; after deduplication and screening, 17 studies were included in the final analytic corpus. The evidence shows a progression from treating customers as financial assets toward models that embed customer forecasts within conventional discounted cash-flow structures incorporating cost of capital and other financial adjustments, but important limits remain. Direct evidence is concentrated in contractual and subscription settings, leaving noncontractual valuation dependent on inference about latent customer activity and irregular purchasing. Finance-consistent firm valuation is also more developed than the treatment of customer-specific risk, and external applications remain constrained by incomplete and inconsistent customer disclosures. Validation has become more rigorous through longitudinal analysis, holdout forecasting, benchmark comparisons, and market-value tests, but remains concentrated in relatively few firms and industries. The review positions CBCV as behavioral infrastructure for conventional corporate valuation rather than as a substitute for it and identifies priorities involving business-model extension, risk treatment, customer disclosure, private-company valuation, and broader validation.