How Big Is the Megaprojects Business? Megaprojects are not only large and growing constantly larger, they are also being built in ever greater numbers. The McKinsey Global Institute estimates global infrastructure spending at USD 3.4 trillion per year 2013-2030, or app. four percent of total global gross domestic product, mainly delivered as large-scale projects. Not at any time in the history of mankind has infrastructure spending been this high, measured as a share of world GDP. The Economist has called it "the biggest investment boom in history." And that's just infrastructure. If we include the many other fields where megaprojects are a main delivery model – oil and gas, mining, aerospace, defense, ICT, supply chains, mega events, etc. – then a conservative estimate for the global megaproject market is USD 6-9 trillion per year, or app. eight percent of total global gross domestic product. For perspective, consider this is equivalent to spending five to eight times the accumulated US debt to China, every year. That's big business by any definition of the term.