Explain the key characteristics of infrastructure as an investment

Infrastructure assets provide essential services, last for decades, and face high barriers to entry through natural monopoly, regulation or concession rights. Demand is fairly inelastic, and cash flows are often long-term and linked to inflation. Economic infrastructure covers transport, utilities, energy and communications. Social infrastructure covers schools, hospitals and similar public facilities, often under availability payments. Revenue can be regulated, contracted or demand-based, as with tolls, and assets are either greenfield (to be built) or brownfield (already operating). The main risks are regulatory and political, construction, demand, refinancing, and ESG. The trap is assuming all infrastructure is low risk: greenfield projects and GDP-sensitive assets such as airports and ports can behave much more like equity.