Kuehne+Nagel earns a spread between what it pays carriers and what it charges shippers, plus fees for customs, documentation, warehousing and supply-chain management. It runs four business units: Sea Logistics (ocean freight forwarding, its largest unit by volume), Air Logistics (time-critical, healthcare, perishables and high-tech cargo), Road Logistics (mainly European and North American overland transport) and Contract Logistics (warehousing, fulfilment and value-added services). Because it owns few ships, aircraft or trucks, profit depends on gross profit per container or tonne and on cost control, which is why management reports conversion rate (EBIT as a share of gross profit) as a core metric.