Historically, assets under management (AUM) have been the yardstick by which fund managers judged themselves. In a business whose revenues come from asset-based fees, AUM should be an effective proxy for what ultimately counts most: revenue-generating potential. The relationship between assets and the revenues they generate has frayed as fund buyers have paid increasing attention to costs, leading the pendulum to swing toward lower-fee solutions. This white paper shows this reality playing out in 2023, with mutual funds and ETFs, and details the many paths to potential success.