The management of capacity is considered from the perspective of institutional asset owners. How capacity differs across asset classes is outlined. Investment strategies that offer greater capacity are identified. A discussion of capacity management for multi-asset portfolios highlights how asset owners should manage investments according to their size, focusing on the relation between potential to generate value and capacity. It is argued that optimal scale need not exist for asset owners with the flexibility to adjust where and how they invest as they grow, even though it may exist for specific assets or strategies. Suggestions are also made for managing capacity when investing through external managers, including ideas for detecting and addressing related agency issues.